When someone special leaves yoou behind

I recently learned that my best friend is taking off across the country. And he's not just going for a visit. I am feeling so abandoned. He says he is not abandoning me but to me that is just how it feels. I feel abandoned, therefore I am. It does not matter that it is not his intentions. For me it is so hard to get close to anyone. On the surface , it  may look like I am very close to someone but when they move on, I just don't really care. This time I do. And I hate the way that feels. He is one of the few I can open up to. One of the few ever in my life to care how I felt and what I wanted. And now he's leaving and I am dealing with emotions that I don't want to deal with. I recently went back on my Prozac so I have real emotions. I hate it. I hate feeling. I prefer to not know what I am feeling, to numb out when this get hard. To only recognize anger and my mania. Now I have to feel and it hurts so much. My heart is broken and he has no real clue how much this is hurting me. I wish something would happen and he would have to stay, but I know that is selfish and that he is doing what is best for him. But it makes me feel so alone and like I am not important enough to keep him around. II know how selfish it is.