It all started so innocently. I was at the dentist's a year ago for a routine check-up and pointed out some tiny ulcers on the right of my mouth. 'It's probably a virus and it'll go,' he said blithely.

How wrong he was. This was the start of a rare auto-immune illness - mucus membrane pemphigoid, since you ask, and only 300 of us have it in Britain - which was to transform my life over the next year physically, emotionally and financially.

When I say transform, of course, I mean ruin, although the outcome one year on, with a diagnosis last month from Guy's (a truly marvellous hospital), is now much improved.

As a freelance journalist, you know you can't afford to get ill, miss deadlines or let people down. This rule goes with the territory for many self-employed people.

I wish I'd rejoined the union relevant to my work, the National Union of Journalists. Union membership gives access to advisers who can help in my sort of situation. And I would have attended one of the NUJ's useful one-day courses on Getting Started as a Freelance (£45 members, £75 non-members).

One of the hardest aspects of the illness has been the 100 per cent uncertainty about how long it lasts, treatment, and when I might be able to resume work. This plays havoc with your financial planning.

My husband and I have deliberately simple finances, which we look at in an ad hoc way once every three months, noting income, outgoings and the overall picture. A recent acquisition was a £40,000 mortgage on our house by the sea in north Kent. This, plus a loan I'd taken out when I'd returned to freelancing the year before, meant monthly outgoings of £450, which had to be paid.

After some months when it became clear that my malady wasn't disappearing like a good virus, this burden fell on my husband. He is a bookseller and poet and by definition low-paid, and this has been a strain. We've been managing, just. But it's important to prioritise financial commitments in these circumstances.

My deputy bank manager, Anthony Galt of NatWest, has this advice on developing a survival strategy. 'Talk to your mortgage provider or landlord. He or she can't help unless they know. According to the Citizens Advice Bureau, your priorities should be: the roof over your head; heating and lighting; water and the phone.'

He adds: 'It can make sense to put down a token repayment, say £5-£10 a month, as a gesture of commitment. Occasionally, a small debt may be written off by a bank, but anyway we do have some flexibility. Foreclosure is only a last resort.'

Talking to BT, the same rules apply. A spokesman says: 'If you tell us you're in trouble, we don't necessarily need doctors' letters. But we can work out repayment plans to suit both sides. If you don't communicate, it looks as if you're a bad risk and we may act accordingly.' If you offer to pay in instalments, you'll find the utilities have more flexibility than you think.

There are other financial implications when you become chronically ill. When I developed a thyroid condition, I was in a salaried media job and had the reassurance of continuing pay trickling into my bank account. This time I was on my own.

One blow was the cancellation of my BMI medical credit card with its £3,000 interest-free capacity for six months. I needed my gut investigated because after six months I was starting to lose weight fast. This was in fact because eating was becoming painful through widespread ulceration, but other symptoms meant that the consultant thought it worth doing tests. Cost: £1,800 upfront, money we didn't have to spare.

I tried to renew my BMI card, couldn't and had to dip into dwindling savings. Never mind the rainy day, it was pouring on our parade and things were getting worse.

Talking to everyone is crucial, but it's especially important with your bank, which can increase overdrafts and find other ways to help. I was able to continue editing my literary magazine, and this modest income (about £500 or so with expenses per issue) was welcome, but obviously wasn't enough.

We started dipping into a reserve account I had simply to survive. At least we'd stopped going out by this spring, which was a saving, but depressing.

We have been forced to radically review our finances, starting with our main asset - our home (see below). Over the next two weeks I will outline other steps we have taken and will consider how I might have been better prepared.

Selling our seaside house seems a sound idea

We have a cottage by the sea in achingly trendy Whitstable, whose worth has more than quadrupled in the past decade. In effect, my husband, Michael, and I have been sitting on our greatest asset, unable to access its worth except by the wasteful dribble of increased loans or mortgage.

What to do? I got two valuations. The first, from County Estate Agents, priced the house at £370,000-£380,000 if we didn't update it. 'An outsider will probably buy it, and we have a waiting list for your address, Island Wall,' said the agent. 'Your location by the sea is what'll sell this house, not a new shower.'

The second agent, Kent Estate Agencies, put a price tag of £330,000 on the house without modernising, £385,000 with repainting and what the agent called 'improved presentation'. So our formula for action became one cottage equals two buy-to-let properties plus income. We were looking for a cheaper, larger house in Whitstable, not on the seafront but on one of the other roads. This could cost some £200,000-£230,000 and we'd still have money left for a smaller buy-to-let property, possibly in nearby Canterbury, a student city. Our mortgage is about £40,000 and we'd want a cash buffer for unforeseen circumstances. If I've learnt one thing from this illness, it is always to factor in the unforeseen.

I consulted Ray Boulger, senior technical manager of Charcol independent financial advisers. In principle, he said the idea was sound: 'Financially, it makes good sense and, equally important, it fits in with your lifestyle plans.'

His advice was:

· Get a good accountant, because as landlords your affairs will become more complicated.

· Use your married status - look at the flexibility of putting two properties in different names or one in joint names. As a married couple, you can transfer property without paying capital gains and take advantage of whoever has the lower tax rate.

· Consider new flexible mortgage products, which allow repayment without penalty. You'll be able to access more money when you need it without paying interest when you don't.

· Don't worry too much about rumours of a crashing market. The reality is more likely to be a slowing down, with benefits for people with enough capital to avoid the negative equity trap.

· Don't get sentimental about properties you're buying to let. Be practical.

· Be wary of offers of new developments paying a guaranteed rent for a fixed period. Why do they need to offer this? And will you be able to afford the mortgage later?

· Remember your tax status and your tax relief on expenses offset against your profit, chief of which is mortgage interest repayment.

As I'm still convalescent, we are not planning to act on this until early 2005. This could be a good thing: we now have leisure to look. So this venture forced on us by harsh circumstance could be a blessing in disguise.