My best guy friend doesn't want me anymore? please read!?

So like back then, he and I would text like crazy and always asking me to hangout with me. He admitted that he liked me. But now, he doesn't make an effort to ask me to hangout or text me anymore. It really saddens me because I miss that and I am starting to like him too. I see him during ping period and he only says "hi" and I try to make a conversation but he seems a bit annoyed. Because of that, I stop trying to put effort because he doesn't wanna respond to well. Plus he has this other friend that's a girl that he constantly texts/hang out. It upsets me that I'm losing him to her. What can I do? I want it to be like the old times. I miss him oh so much =( please don't tell me to forget him/move on cause I truly miss him as a friend and I don't know where to start....