Dudee honestly I've been in the same situation but, it will pass, I know you feel sad and left out, but aither this kid is mad at you about something and he just doesn't want to tell you, or the friendship got steal, aither way don't attach yourself to them just let it flow you will find better friends, and if he comes back great and if not then even better you'll see if he really is your friend. Ik its really sad to let a friend go but if he's making you upset then just cut him off, or don't talk to him much. Don't stress so much about that, he'll see that you're moving on with your life and he might try to get back in it. Idk how to comfort people much lol but I've been trough this and it will pass, just do whatever makes you happy, it's better to not have any friends and be happy with your life then to have a group of friends that make u miserable. Hope this helped 😅❤️