Please someone tell me what movie this is!!! Vampire film...

Im not talking about once bitten but is similiar. I saw it when I was little and I just can't remember what it is called I really want to see it again but I can't think of the title. All I can remember is the main actor is male and he's kinda of a teen hearthrob and I know the movie is from either the 80's or 90's but im pretty sure it was the 80's. It might have been a made for tv movie. I think it might have been Matthew Perry or Kirk Cameron but im not completly sure. The guy in the movie is similiar to them. It's similiar to Teen Witch,Teen Wolf,and Once bitten. One scene I can remember is the guy's in a library and he's with a girl (maybe his girlfriend or just friend) and he walks by and sees a mirror and he sees her reflection but he doesn't see his. Then he finds out he's a vampire and acts very strange and tells the girl he has to leave. He leaves and she gets mad and thinks he's weird. Could someone please tell me what movie this is?!?!