Lonely or too dependent on others?

Ever since I can remember I have been PETRIFIED of being alone, I can't sleep without my dog or boyfriend and at work if i have to be at the desk alone i freak out a little... I grew up with two older sisters and one younger brother and then when I was twelve my parents had another girl so i've pretty much always had someone to be with... Well the problem is i am in the army, away from the states and my boyfriend just when on block leave, before he goes to Iraq in a few weeks, right now i am freaking out and kinda feeling like Christina Ricci on "Black snake moan" its only for twelve days and ten are already gone, i am experiencing bad headaches can't eat and can only fall asleep becaus i have stayed up so late... what's the matter with me? and how can i cope when he is gone for fifteen months? I really don't want to find someone else... any suggestions?