Does my friend find me annoying?

we've know each other since 8th grade but we went to different high schools until i transfered in 10th grade to his school, we use to chat and he seemed really different unlike the shallow ones at my school so i decided to leave them and go to his school, which i now regret. We had the best of times at school but when we hit summer break he just stopped, well we did go to the movies and stuff but he stopped talking to me more and more and now im worried. He started to sleep during the day and stay up all night because he claims to hate talking to people, ive talked to him about him being depressed (he never wants to go out anymore and he doesnt talk to anyone) and hes like its none of your business. I got him to go to the gym with me but he only went like 3 times in 4 weeks and he just had this different attitude, he was so pessimist and mean and I've always tried to please him but now its just so hard. Ive tried txtin him and but he always has his phone off and basically not in the world of the living anymore. all he does is watch anime all night long. so what do i do? i dont want to leave him because i know he needs help but i just dont kow what to do, should i leave him? but what kind of friend does that? i mean he was cool but now hes always being a and when i try to tell him that in a joke hes like i am one so deal with it, is he just going through that phase in life? we're both 16