Seperation anxiety in an adult?

I have been with my boyfriend for 3 years and we have been living together for 2 off and on. In the begining we had a pretty rocky relationship I went away and we both cheated on one another it was when we first started dating. Now it is 2 years later and everytime he leaves me over night or goes away upstate to see his parents (which is where he is from and I am as well) I get so much anxiety. He does not even call at all, I have to call him. Then he says he is doing something with his friends and will call me later but later comes and no call. I call him. We have a serious relationship. I think about him 24/7 when he leaves and he does not think about me at all it seems, he always says he is just hanging out with the guys and family and I have nothing to worry about but I have trust issues and it bothers me. My mom left when I was 2 and I remember crying none stop when she did I know it was a while ago but could it be I have a seperation anxiety, I hate when he is gone, I go CRAZY.