Most Helpful Girl
So basically wants to be a single 21 year old who can party and sleep around then once she has finished having her time off and the casual sex/meetings become lonely to her and she feels like shit and misses someone who cares about her, then she will come running back to you, and tells you she misses and loves you but still needs time to think so she is stringing you along, hoping she will get back with you. When you are in love with someone you don't need time to think you don't need to figure out if you love them. Move on.
Most Helpful Guy
There was a time when she was having fun and felt free, while in a relationship with you. But at some point, she stopped using those words to describe your relationship. But, because we all want to have fun, and because we basically are free at the core, her spirit rebelled at this. And that's why she left.
She definitely loves you but was feeling so trapped that she needed to get away from you to breathe easy. She will come back again if she starts associating you with the words "fun" and "freedom".
Think back to the beginning and how it felt. Then try to find the place where YOU stopped feeling fun and free, and instead became "serious". We are taught that we either have fun , OR are in a serious relationship. As if you can't have fun in a monogamous relationship. And we are taught you are either free, or you're in a relationship. As if a relationship is a prison.
Who would want to go to prison and not have fun?
So practice your own sense of fun and freedom. In the end, it doesn't really matter if she comes back or not. You may end up with another one who's even better. Yes I know you're thinking no such person exists but one time, you didn't know this one, and she did come along. It can and will happen again.
Breathe easy and take your time. Focus on you and on what you're wanting in a mate.
I hope this helps a bit. Good luck.