What should I do 💔

So there’s this boy I have madly fallen for... he knows I have told him before, he has felt something for me or so that’s what he would tell my sister, we went to school together our last year together I decided to give in and talk to him I was so nervous there was problems here and there between other people like another male telling him to back off because he was interested in me and a female intervene in between us she would do everything just to talk shit about me to her friends even to him!! We got to a point that we were comfortable talking hanging out during school, he was going to ask me out but all this bullshit came about, nothing happened!! Quick note he is a very shy not loud person he likes to keep his stuff on the down low, I think that’s what I liked about him I mean I have the strongest feelings for him ❤️ the day of graduation he didn’t end up walking why well he had his reasons but he did get his diploma I asked to take a picture with him we did I was very happy 😊 emotional in the inside, he didn’t mind we hugged like from the side to take the picture together the female I spoke about earlier was there she didn’t like the idea, their close friends to top it off, now I’m telling you this but it’s half of the story!! Fourth of July came around I had heard he was hanging out with her and another friend!! It kills me now high school as ended that has ended and I come to find out he leaves for the military in a couple of days, I knew he wanted to do something related to the military and I would tell him I was happy for him and proud of him it hurts me but I would never stop him for my feelings, my friends suggest I text him tell him how I feel but I’m scared he will give me the cold shoulder or tell me he doesn’t feel the same way we haven’t texted in a long time the day I graduated I asked him and showed him my phone if that was his same number since I still had it in my contacts he said yes!! What should I do? Please help me?!