Why do I keep thinking about her?

I went on a few dates with a girl last year, and the first few dates were ok, not spectacular but I liked her.
She randomly stopped talking to me but then we started talking again towards the holidays. We went out again and she explained what happened. She got into a toxic relationship, and got into hard drugs and things got bad. She's not on them and she moved home, but she didn't want to rush things.
We still had sex that night, but it was absolutely disappointing. She put a lot of pressure on me with her history and stories she told me while we started and I struggled.
She said she wasn't gonna hold the first time against me, but canceled the next date and later saying I should move on and I'm way too good of a guy for her and I'm not gonna be good for her. Later she blocked me because I thought she was being hard on herself.
Months later, I connected with her on Snapchat, which she changed her story again and it was weird. Instead of talking about the drug addiction issues and things she was going through, she said we didn't vibe very well, and she said I needed to move on. I accepted it, cause I was disappointed and I didn't understand why.

I didn't delete my Snapchat, but I just removed the app and I never went back on cause I'm sure she was gonna unfriend me and the situation hurt.

It's now been 6 months, and my buddy likes giving me a hard time about her, but I've started to think about her again and I don't know why.

This was only the second girl I went out with after my engagement ended two years ago, so fyi
Why do I keep thinking about her?
Add Opinion