I need a guys perspective

A guy asked me out. I let him down easy and we’re cool. He got a gf like right after. But when we see each other at school and he’s with his friends, all his friend start teasing him and looking over at me and sometimes I hear them say like “ooo *i sett his name* look who’s here” or “oh hey there’s *insert my name*”.

so what do u think this means and why r they doing that? I wouldn’t be asking if this happened rarely but it’s like everyday and it’s annoying me and making me feel self conscious