Worried about male ex-friend who used to sexually harass me?

When I say "sexually harass", I mean someone I knew who kept talking about sex and other very personal stuff every time we met up or talked to each other. They also kept asking if I wanted to "do it" and other suggestive stuff. I'm not a slag and not at all interested in this berk, and he was really creeping me out so I blocked his number and blocked him on Facebook, and luckily I haven't heard from him since. I'll also make it clear I never gave in to him, and he never touched me or anything. I never see him in person anymore (thank god) but even though I've blocked him and he's out of my life, I've recently realised that this has had an scarring effect on me. I got a notification on FB saying "Do you know this person?" and it was HIM. I immediately deleted the notification, and now I'm really shaken up by the whole thing even though it was just a standard notification. I can't stop thinking about him either because I'm nervous about the whole thing. Also, I may see him at graduation this autumn and I'm actually scared to see him in case he tries to talk to me or do something. I'm also worried he might start spreading false rumours about me and then people at graduation won't have anything to do with me. My family are coming to graduation and know about this sex pest. Should I tell my tutor at uni about him so they know the situation? What should I do about my anxiousness about him? How can I move on from this?