Welcome here to the Forum, which is a pretty good place to come to get all sorts of advice. There are plenty of folks here who have had a great range of experience and would like to help.
I'm afraid your question is a a bit brief, and as a result it is very difficult to know what to say. If we knew a bit more about you and the problems you face it would be easier.
In the meantime I guess there is one general sort of thing one might say and that happiness and being happy with one's life is not realy something one can consciously try to attain, but seems to be a sort of byproduct of other things, like security, occupation and accomplishment, loving and being loved.
Perhaps you might like to come back and say more?
It's most likely your currents friends won't be part of your life when you try and rebuild it, it's upsetting but you will gain other friends as you become stronger along your journey, the main point here is that you have to become happy once again, sure there will be days when you fall back, but I consider this as gaining momentum, ready to tackle another issue, learning something each time it happens.
Hope you are able to reply back to us and give us a little more about your situation. Geoff.