<human>: Could you distill the essence of the text into 1-3 sentences?

Three years ago I worked with a bloke who I used to consider a friend - not a close friend, but we would sometimes chat on Facebook and he was part of the group of friends I had in the area.  I moved away and had very occasional contact with him.  About four months ago, he opened up to me about something quite personal and I was nice to him about it.  Since then, he has become more and more obsessed with me, to the point where it's making me very, very uncomfortable.

He likes and comments on *everything* I do online within seconds of me doing it.  I had to stop using some of my social media accounts because I started to feel suffocated and my friends were sick of him butting into our conversations.  He messages me all the time, calling me cutesy nicknames and being very overly affectionate.  He doesn't get the hint when I ignore him.  When I went to visit my old group of friends, he turned up uninvited to where I was staying two hours before the event we'd arranged, and insisted on seeing me every day I was there.

I've recently found out I am moving back into the area where he lives, and I'm not sure how to deal with it.  I would usually be so excited, as it's a fantastic opportunity for me career-wise, but I'm starting to get panic attacks whenever he contacts me as I'm so creeped out by him. I've maybe been watching too much Law and Order, but I can see him becoming worse and worse, turning up to my flat unexpectedly, contacting me literally all the time, inviting himself to everything I do.  

I don't want to say anything to him and hurt his feelings - I know I may need to eventually, but I'm worried the rest of my group of friends will feel uncomfortable around either of us and I'll get pushed out, so I'd rather avoid the direct approach if possible.  More seriously, I could also see him getting very angry about it as he's a sensitive person.  I don't know what to do.
<bot>: Creepy ex-coworker has been stalking me online for a few months and I'm moving to his area soon.  I don't know how to get him to leave me alone.