Help with crush

So i am 19,guy and bisexual in the closet.First day of uni i met this and we exchanged some words nothing special.Third day all of my uni classmates arranged we go to a place for cofee and have a chat.He came lat and sat in a table afar (we were like 30 people and we had covid so yeah ) He smiled towards me,greeted me( i was the only person he greeted but he knew many from there) and he was constantly smiling towards me,blowing kisses at me and etc.Finally i decided to sit at his table and he was teasing me , filling me with sexual jokes , being touchy etc.We exchanged social, he was texting me with memes and selfies, talked to me in group chat and replying to my stories on insta.Fast forward to the day we closed due to covid, he gradually stopped initiating conversation on messenger,stopped entirely talking to me on insta and didnt talk to me in group chat.He was teasing and joking around with an openly gay guy and started calling me his bro,best friend and other straight terms.He one day talked to me about this one girl in our class who truly is really thirsty for him and cant wait to have sex with her etc.At some point i asked him if everything was okay and why he stopped texting me or behaving with a specific manner and he was like no ? you crazy? you know you are one of the only people i call friends.He still has this same attitude (university hasnt opened yet) and he has said in the past towards some girls that he doesnt look at boys (that he is straight) I don't understand why he suddenly acts like that towards me? He is now more close with this guy and the girl who wants to **** and barely talks to me.He still acts friendly towards but i feel used since he doesn't seem to really care.Can you guys give me an explanation of what is going on? I'm really confused.What should i do?