I miss my bestfriend, and i don't know what happened between us...?

I know that you won't get over him, but if he doesn't want to be your friend anymore you wouldn't want to force him into anything. If you really want him to be your friend again, try talking to him, if not, try doing things little by little. Maybe you can catch his attention, do some nice things. Also, try thinking back to the time just before he didn't want to hang out with you guys anymore. Maybe there was something you said or did wrong that might offend him, or maybe you just misunderstood something. Try thinking things from his point of view. It might work. Also, maybe there is something going on in his private life that you might not know of. Do not think too negatively about what is happening between you and your friend. If you keep worrying about this situation, the only thing that will happen is that you will damage yourself beyond repairs. It's good to ask other friends or family about this situation, I hope you can figure this out! :)