Priortise and try to make things easier on yourself. You can't deal with all this at once, and some things are more urgent than others, such as your exams, so do what you can to relieve the pressure in that area and let other things lie for the moment until you have a bit more headspace. You have a lot to get through practically and emotionally so don't expect things to be right straight away, give it time, give yourself a break, allow yourself to let things go and focus on what's really important for the time being if you can. I've been in a similarly bad way and it's only by looking back now that I realise it all just took time, and eventually I started to get through things. We all have these really bad periods, and you're having a particulary bad one, which really sucks, but the main thing to realise is that it's not the end of the world and you can get out of it, you just have to be kind to yourself, decide what's important and what's not and try to get yourself to where you want to be in, say, a year's time.
Try to find someone, anyone, to talk to (feel free to PM me if you like) and let things out as and when you're feeling them. You'll have good days and bad, but don't feel like you're going back to square one, sometimes it'll feel like you're getting nowhere but eventually you'll realise that you are making progress. Most of all, and I'm going to say it again, give yourself a break. Be realistic about what you expect of yourself, allow yourself to just cry and stay in bed from time to time, but don't allow yourself to wallow for a long time or start to feel self-pity. Try to find things that are good in your life and also, don't forget to ask for help - people can't and won't help you if they don't know what you want. It's ok to say to someone, "I just want a hug" or "I just need to cry" and to ask them to be with you. Most people will be flattered that you're relying on their support.
Good luck.