<human>: Provide a brief overview of the text.

A little backstory first. I dated a girl for about a year. We clicked very well and I truly loved her. I was 19 (20 now) and she was 18 (19 now). I know we're young but we both kind of went balls deep into this relationship which I now realize was a big mistake. Regardless, I ended up breaking things off because we both weren't happy anymore. I left the door open for a reunion sometime in the future but we ended up drifting apart and basically hating each other. At this point in my life, 6 months after the break up, I don't love her but I still care about her as a human being. I recently learned that she's gone back to casual hookups and just behavior that is completely different than what we had together. Partying/drinking 4-5 times a week, stuff like that. When we were together, she was a shy girl who wasn't really into any of this stuff. She vowed to stop sleeping around because it made her feel pathetic and she felt like she was being used. However, after we broke up, she's made a complete 180. It's like I don't even know she is anymore. Now, before anyone jumps on my case, her personal life is none of my business and I've gone NC with her for over 2 months now but I'm hung up on what's really going on with her. I don't know why this girl acted a certain way with me and then a few months later is a completely different girl. My concern is that I feel like I was almost played. I'm having a hard time accepting that I might have completely misread this girl and that saddens me as does knowing she's back to "being used." Does anyone have any similar experience with a gf who did a complete 180 after a breakup? I just need some advice on how to get out of this mental funk.
<bot>: Ex gf isn't the girl who I thought she was and I felt like I was played. How can i get over this type of thinking?