scared at school; what should i do?

hi ladies, i have a reason for being afraid of walking in my class hallway all the time. it's because of this boy (Call him J) that's almost went too far with me as in like trying to get with me. so we were best friends during sophomore year and at new years i went to his house. my boyfriend was a bit wary with me and him as friends, which i know now why, and he kept like talking to me and confessed he liked me. so i told him he's only a friend and that i love my boyfriend very much and wouldn't ever risk it. so he moved on and we kept bein friends. but not too long ago, it was about september when he was invited to a sleepover that was out in my friends backyard along with multiple people. we all had separate tents, girls in one, guys in another, and one for my friend and his girlfriend. so i had no idea J was coming to this party, and that's why i went. i didn't want anything to be awkward. so when it was time to go to bed, two of my guy friends ended up sleeping in the big tent with me and two other girls. then J suggested he stayed with us so the girls agreed being friendly. while i was half asleep and very sick (i had a migraine, it was cold and rainy that night also) i felt a hand slide gently under my stomach slightly touching my boob and i freaked out. i was so shaken and all i could think was omg i need to leave. i'm not aggressive but i did tell him no and  to back off. he did so and then i was asleep and woke up by J holding my hand, and holding me in a position where i couldn't get out. the night went on and he finally backed off and in the morning i had my boyfriend pick me up and i told him about everything. he straightened J out and told him never tobago near me again. i blocked him i everything but when i pass him in the halls he always raises his eyebrows at me and creepy shit. i don't know how to now be scared...