man -- i read all of your correspondence over there...nobody seems to be saying what's obviously there. i'm pretty sure she was testing you and you failed big time. wanna know what went wrong? she was looking for a little reassurance, no judgment from you, and for you not to get bent out of shape. you did OK with the reassurance part. Your biggest mistake was getting so obviously defensive and giving her a chance to end the "relationship" by saying "if...blahblah...then maybe we shouldn't see each other anymore." over one little makeout session????? ARE YOU INSANE?????
she was not looking for your answers to her but HOW you answered. you obviously got rattled enough that you were ready to cut and run on her...over something little and stupid. i'm 100% SURE she was taking notes on that!
and btw -- 9 out of 10 times, when you say something about "maybe" not seeing each other anymore, the girl will be HISTORY. in a heartbeat.
probably this girl liked you quite a lot -- though there is a chance that you can get back with her, i think....
in the future -- when dealing with that crap (which is NOTHING compared to what she will throw at you when you're dating), you absolutely MUST be calm, cool, objective, and reassuring. these are masculine qualities that she's looking out for.
hope that helps.