Character stuck in a rut?

Ok I have a character that I am kind of "being". I haven't started writing from her point of view yet but I've been acting like her online. What I mean is I have accounts for her that I have been acting like her on. The problem is she seems to be lost in her own feelings of hopelessness and I can't really find much past that. The only time I can make her have fun or let go is when she is with her best friend, but she's still sarcastic and has a very dark humor. I've been trying very hard to see what else she has the potential for but I can't seem to make her expand into a beleivable realistic character. Can someone please suggest to me how I could do this?