what should i do with her?

so i met this girl over the summer. our friends were dating so we saw eachother a lot and pretty soon we had a thing of our own. it was never official but it was exclusive for a while. School started and it was hard to see eachother. we only live a good half hour away but neither of us have a liscence. there was a music festival right before school and we had a falling out afterwords. I thought it was because she was worried about not seeing me during the school year because thats what she kept telling me. so i showed the innisiative and found times i could get up and see her but she kept making excuses not to see me. i figured it was over or she just wanted space so i stopped texting and calling her and 2 weeks later she called me with this big story that she had done shrooms with some friends at the music festival and she had been coming down from that high for two weeks and because of that thought we were too different to work. I was mad at her over the whole thing but i still liked her and for some reason took her back without really confronting her over it. i know i let her walk all over me on it. We spent about two weeks trying to see eachother then figured it wouldnt work out cuz we never saw eachother. we both went out and slept with some other people and had some slings then about 2 weeks later she drunk texted me. i dont know what she said cuz i couldnt read it but the next day she started texting me again. about a week later i finally got up to her house to see her adn we had a good time. it was the first time we had actually slept together since i met her. Afterwords we maid plans to see eachother again and we had it set up so it would actually work. were more of an open realtionship and we were talking for a few days after but now she stopped talkign to me and usually at this point i let them go and call it but for some reason i cant let this girl go. So am i just being used by her or should i give her space? I am not sure what to do here? im usually better about this stuff but idk. was this just finishing business or what? i could use some advice on what to do here. for some reason i cant let her completely go. right now im not trying to talk to her right now and give her space but i think im letting ehr walk over me. advice pleas?