Why does he always watch me?

HI so there is this guy that I use to hang out with and we were really good friends. Everyone we were friends with thought we were dating and just keeping it a secret. well we had a falling out and have not spock for a while. I moved away from the town we meet in to finish college and one day I was walking down the hall and saw him. I found out later that he had moved up to the same town I was in. I see him all the time in the halls of school and every time I see him all he dose is just look at me. he never says anything. he just watches me. and I want to know if he doesn’t want anything to do with me then why is he always watching me? Is he scared to talk to me or regretting what happened?