How can I form relationships with other people and not fear the unexpected?

I have abandonment issues from my fathers suicide and to cope with it I eat. My social skills are lacking and I feel that I can't really function in regular society. I'm 20, I've never really had a boyfriend and an adequate social life. How can I be able to form relationships with other people without fearing abandonment again, and not rely on eating to feel 'safe'? How can I stabilize myself, start being an adult, and yet still 'feed' the kid part of me that never really learned things that I should have been taught a long time ago?