I need relationship advice. I do not know what to do. I'm a college student.?

There is this girl I have been dating with for about 2 and a half months, but we would only hang out maybe once or twice a week. Recently, in the last 4 weeks or so, we have been getting closer and we started hanging out maybe every other day. I felt like we were a lot closer, for example, started holding my hand when walking around campus, knowing that her friends might see her. So today, we had a conversation and she brought up that we were only dating,like we can hang out or go out with other people, and she wasn't ready for a relationship. (she never had a boyfriend). I asked to be exclusively dating, but she thought it was the same thing. I think i totally blew up the whole situation, and got really upset when she told me this, and by the end of the night, i told her that we shouldn't go out anymore. I don't think I was thinking straight at the time either because I stayed up all night the previous night studying for a midterm that I felt I failed, and I didn't have anything to eat since the morning (I was talking to her at night). She seemed very very sad, but agreed. Last week, we were perfect. This week, things went down the drain. I still want to be with this girl but I don't know what to say. Am I just too jealous, selfish, or what? I feel that I like her to a point where I wouldn't feel comfortable dating anyone else but her (and i told her this), but she obviously doesn't feel the same way. Maybe she isn't all that in to me? But she was tearing up when I told her we shouldn't hang out anymore. I don't know what to do. Please help!!