How to battle pain and deal with feeling a void?

Well I have unmet emotional needs from my father... I don't feel love from him... And I used to be christian and I obsessed over God, and it was like my way to cope with the pain... But now I am atheist, and now i'm feeling the void and pain.. I have a girlfriend, but I noticed that i'm so clingy and that I use her to fill my void, which I know isn't right.. I start getting anxiety when I haven't spent time with her.. I know the anxiety is from me being afraid of feeling alone and feeling the pain.. So I know that what I have to do is separate myself from her, and confront these feelings.. But I don't know how to deal with them.. Will the pain ever go away? Or will I just have to cope with it. What steps can I take to deal with it?? Also, I am afraid of love.. When I feel love from my mother, that warm feeling, I try to cut if off cuz it scares me... It's probably cuz with love, your vulnerable.. How can I deal with that?? My mother is going to get me a counselor, but before she does that I want to see if there is any possibility of me dealing with it on my own... This isn't fair to my girlfriend.. I want to love her, not use her...