I know how you're feeling, some time ago I suffered with depression and anxiety and couldn't see a way out. I had friends that would always ask me to come out, but I just wanted to stay indoors and hide away from the world and eventually they stopped bothering with me. Great friends, eh...
I eventually figured out that the only way out of the situation, was to change the situation. It sounds like you have a form of social anxiety as well. The only way to combat it is to face your fears, get out amongst people and make some friends, which university is perfect for.
Not only that, but being at university you'll hopefully make some achievements, brilliant depression killer.
Ever since I broke out of the same routine every day, things started to change. Sure, I had anxiety through a lot of it to the point that I felt unwell, and sometimes still do have anxious days. But I've learned to deal with it and nothing kills anxiety like getting on with it, just like nothing feeds anxiety like sitting there and worrying about it.
That's basically it. If you don't change the way you live, the way you live will never change. The only way to achieve happiness is to make changes.