Girlfriend Broke Up In June, Still Have Been Talking An Seeing Each Other. NEED ADVICE!!!?

My girlfriend of 3 years broke up with me in June stating that she needed to find herself and that she is depressed. We had an amazing relationship since college, and I was going to propose to her in Oct.She told me that there was no other guy in the picture. Since then, we have seen each other a good amount and speak a lot. Even though we have seen each other she , there are days when she acts so loving, like her old self, and there are days where she is distant and cold and I have been there for her to talk on the phone to or just a shoulder to cry on. I spoke to my mother and she told me " If you want her back, don't get together with right now, show her that you have a life of your own, and don't call her, let her call you. Is that good advice, should I let her get in touch with me? Does absence make the heart grow fonder, or is a long term relationship breakup more like out of sight out of mind. After a relationship is over, can you rekindle it? what we had was great.