This guy won't leave me alone! help!?

Wow your ex-friends are jerks. You're right. Just because someone is creepy and weird with no friends doesn't mean you have to pity them. It's your life, and if this guy is making you uncomfortable and his circle of weird friends and of your mean friends is really getting to you, find an activity that will keep you preoccupied until they realize they aren't getting to you. Get a boyfriend that you actually like, and some friends that aren't jerks, and spend enough time with them so you forget about this awkward situation.