What is wrong with me?

I had bad experiences with people a few years ago that cause me to become depressed then a nihilist. At the end of 09 something happend that made me want people in my life again. I have been talking to everyone i know, making up with old enemies, and going to parties. But when ever its time to leave or say goodbye i feel so empty. I feel like i have noone. why do i get this way? how can i make it stop?