Whys he acting this HELP?

Theres this guy i sorta know but dont talk to at school and i used to sorta like him but then i got over him because im 14 and hes 3 years older so i decided it was silly. so lately ive been ignoring him, not looking at him when i'd usually be checking him out. yesterday i walked by his locker and he pushed one of his friends into me. today i walked past him and he threw something infront of me. wtf?