The dilemma: I have just finished university and I had a really tough last year, due to unfavourable relationships with friends/house mates and an ex-boyfriend. I am now living with my parents, and have had counselling as a result of my experiences. However, I am having problems with two friends I kept in contact with from school. We went to different universities and now that we are back I find I get on really well with one of them but not the other. The girl I'm struggling with has changed a lot, as I imagine I have. I have found her increasingly selfish, rude and insensitive which makes me aggressive and defensive around her. I am determined not to let her get the better of me. In her defence she has a lot of personal issues and a dysfunctional family, so she has little support. I have tried to encourage her to seek similar help to me, but to little avail. I wish to step back from this caring role I seem to have placed myself in, without severing myself from them. I am trying to get a job, but have been finding it very hard. I am trying to look to the future and be positive, but feel I am being stumped by my problems with this difficult relationship.

Reading your letter made me heave a sigh of relief that my twenties are over. Not because your problems stop in later years but because your ability to judge them in some kind of context does thankfully improve a little bit. You've had a tough time recently and I think you're feeling pretty vulnerable. Ironically, it sounds like your friend is suffering a similarly difficult experience. Unfortunately, at the moment instead of that giving the two of you some common ground and moral support, it's serving to exacerbate the situation. Maybe you're struggling to be honest with each other about your feelings and therefore it's causing these misunderstandings? The ideal solution would be that the two of you sit down and try to rediscover the elements that made you befriend each other in the first place.

First you need to ascertain whether your recent painful experiences at university have made you unusually sensitive and perhaps guilty of slightly over-reacting? When we have been hurt and are at our most vulnerable is often the time that we are most likely to cause other people similar misery. Is it possible that you are thin-skinned at present, and because your friend is not particularly diplomatic and has issues of her own you are super-sensitive to her remarks? Threesomes are always complicated and such friendships often stop being viable as you get older and hanker after an alternative form of communication to the one offered by a mini gang.

You may have reached a watershed moment when you need to re-evaluate your relationships with both girls. To do so you need to try to break the block the three of you make up into its separate components, and reshape it judging each friend on their individual merits. There's no knowing until you manage to disentangle this menage a trios what each of you individually has to offer the other. One thing is certain, however, and that is that no pal should be discarded lightly. Friendships formed in our youth, if properly maintained and guided through difficult times, provide a really important support network and memory bank in later life. If you can and do manage to nurture your relationship with both girls, I'm sure that the efforts you make now will pay huge dividends in later years.

That's all on the plus side. More negatively it is possible that your relationship with this particular friend has run its course? Perhaps you're now too similar to get on, or have developed personalities that are incompatible in the years you've been away. If that's the case you don't need to feel bad about it. Brutally speaking, shedding people and habits is just a natural part of the growing up process.

So let's not be overly dramatic here. Both you and your friend are going through tough times and much of what you're experiencing is part of that inevitable business of maturing. If you're guilty of anything I suspect it's being over-anxious about things which don't warrant so much of your attention. Take a step back from the friendship, focus your energy on finding a job and starting your adult life and you'll soon be too tied up in the business of living to give so much space to this relatively small irritant. Analysing and criticising your pal is a waste of valuable time when your efforts should be focused on finding a job, gazing at your own navel and establishing your independence. Once you are employed and meeting a new crowd you'll see these worries for the post college blues they most probably are.

If you, too, have a dilemma, send a brief email to mariella.frostrup@observer.co.uk