OK, I see two issues here. First off, leave him be. Don't contact him, don't facebook stalk him, don't go out of your way to see him- in fact, go out of your way to not see him. Let him have his space, give him one of those big, square states out in the mid-west as space. Contacting him to say "I've been in your face lately" is just more being in his face, be out of his face. If he wants to talk to you, he will, if he doesn't he won't.
Second issue, and this is the important one, is to figure out why you are suddenly so infatuated/obsessed with him. If you never very attracted to him before and now suddenly you are all up ons, this suggests to me that it isn't about him, it is about something that he represents to you. Ask yourself the following questions:
- What is it that suddenly makes him so facinating?
- Exactly when did this facination start and what could have triggered it?
- Does he remind me of someone else? If so, who and and am I projecting feelings for that person onto him?
- What does he represent to me? Is he symbolic for something that I feel that I am currently missing in my life?
By deconstructing from where your feelings stem, you may be able to find a rational explanation for your emotions and get them under control. I know that some people are going to be all "oh psychoanalytic process blah blah blah", but there is something to be said for trying to figure out the deeper meanings behind what we feel. By obsessing over why you are obsessing over him, you may find that you are no longer obsessed with him.
And pay some attention to your boyfriend.