advice?

so i am a lonley guy 18m and i dont really have friends anymore . i only had one friend “close” to me and i knew that he didnt really care much anymore about me but but was always there for me when i needed him. he helped me out when i was homeless by giving me some spare clothes and offered some other things. i told him a lot of personal things about my life and i was very vunerable to him despite me still seeing signs that he was just being performative, and i did still trust him . we were childhood friends and we only hanged out about once a week but i still saw him as someone i could talk to , we became distant towards each other because he is busy and also has another main friend group . but about 2 weeks ago i sent him a text on friday asking if he was busy, no response. i called him and also had no response. i just thought he was busy that weekend so i left him alone but i found it strange that he didn’t want to atleast answer back to me. next weekend aka this weekend i ask the same thing. i ask if he wants to hangout , no response, call, no response. i then get kinda worried so i ask one of his friends to ask why he hasent talked to me in 3 weeks. he responds back to him just saying “interesting” i get kinda worried of disheartened and i am confused on why he doesn’t want to talk to me. i ask further and i just find out he doesn’t wanna be my friend anymore but i really dont know why and i am dwelling on things. he knows i been going through a lot in this stage of my life and whatever reason he has against me is totally fine but i just want to find out why he doesn’t want to be my friend anymore out of the blue? or atleast tell me the reason why, it could be anything for all i care about i just want to know. i am thinking of confronting him in person at school about it as my final act but if he just walks past and ignores me then i guess it’s final. any advice on what i should do? also, nobody else knows why he doesn’t want to be my friend anymore including his friends. he hasent told anyone why.