I'm so sad right now i need help?

My girlfriend is moving after her graduation. She's 18 and im 19. at the same time i am going to military basic training. She said she doesnt want to have a relationship in college. I am so hurt right now it seems like she doesn't care about me at all. Last week she said she was falling for me. WHY IS THIS HAPPENING?!! I am so hurt.... I know she will meet a lot of different guys in college. It hurts me imagining her being with another guy. She'll be partying her *** off while I'll be doing all the hardwork :(