awkward position

so at work theres this guy that coincidentally lives in the same apartment complex as myself and ive seen him around the plant a lot more lately. he's a super flamer and because the people i eat with see him waving to me, they make fun of me with gay jokes. he comes up to me and talks to me about a month ago and asks if i have any good dvds at home. im thinking that he wants to come over and borrow some so to avoid having to see this guy ever...i tell him no i dont have any dvds. then he asks do you have any pots and pans? and i tell him no i dont cook. and im like geez this guy wants to be friends w/me or some shit. ugh. so i told my coworkers of this and they make even more fun of me. then lately ive been getting emails from him to my work email address. like those joke emails that circulate through the office. and he's a production worker taht doesnt work with a computer or has a hospira email account meaning he goes out of his way to send these emails to me. so i dont really think too much of this.

then yesterday, the wife of one of my coworkers (who works with the gay dude) tells her husband that the gay dude asked if i was in a relationship with anyone and how much he likes my body and crap like that. and now my coworkers are having a field day with all this and loving it. im just trying not to throw up. i try to shake the sick feeling in my stomach with some breakfast so as im standing in line in the cafeteria, i feel a hand gently caress my bottom. i turn around and its him smiling at me. being the professional that i am, i simply step out of line and go back to my office to cry. now if this was anywhere else this dude would get a good beat down, but since i cant kill people at work, i just walked away. some of my coworkers witnessed this caressing and think its hilarious. and now im thinking of heading to HR to file a sexual harrassment suit. is this warranted?