Ghosty, I don't really know what's going on (I know you're having troubles with your sister and her husband etc), but you've got to remember that even in the past few months you've been taking proper steps to make your life a bit more like the life you'd like.

If I've noticed anything is that everything changes all the time. I'm not even sure there's that much we can do to steer our own course, but every now and then we end up somewhere comfortable without remembering how we got there. And sometimes life is just shit for a while.

But if you really do feel unable to work out an escape plan it's worth talking to someone about it (advice admittedly I've never followed- but I should have done because I'd have wasted much less time if I had). There must be some sort of counselling/ advice service at your uni, it might be worth looking into it.