[Gambit]

Don't think of your relationship as "on" or "off." I had quite a bit of trouble with that myself, and I know a lot of other guys do too. Goes back to my guys vs. girls stuff in the last post. She doesn't hate you, she still cares about you (can't really wipe away two years in a week). Make your relationship a little more casual, one-day-at-a-time kind of thing. She was probably accurate when she said she felt smothered; that's common, as is the "she's found someone else" paranoia. At this time she doesn't want someone who's constantly at her side. All the "rules" and "restrictions" are just her way of trying to establish herself independently. Instead of all that, just get together once a week or so for a movie or dinner or some other public activity. Doesn't have to get romantic or even very personal, just be available to talk to if she needs it and meeting regularly to keep in touch. "Us" talk should be kept to an absolute minimum for a while. She'll figure out pretty quick if that's what she wants, less, or more.
You probably need to find someone else in RL to talk to about this, too, preferably an older male buddy - older thus hopefully wiser, and the closer to your own age the more important they're male lest you get caught in a rebound relationship. Father, uncle, best friend's dad, youth minister, grandmother, or something. We're helpful, perhaps, but you need face time.