i [20M] want to get back a girl I dated a few years ago [19F]

Basically, I dated this girl for 2 weeks 2 years ago and when I see her, I can't stop thinking of her, she is all I can think and talk about, and I haven't even talked to her since we broke up. The interesting thing is that I broke up with her, the first days when we started going out she showed a lot of interest in me, but the last dates, she was scrolling tiktok with me near her holding her hand, I got mad, and broke up. Since her I couldn't find a girl I REALLY like, and ended up breaking up with all the girls I've tried to date.

Another things is that after we broke up, some rumors came up, that she did me a blowjob, which isn't true, she blamed me for spreading ts. Later I found out it was some jealous guys trying to get at her. When she confronted me back then, she told me "I NEVER WANT TO SEE YOU AGAIN", and she was very mad.

Another 2 years before we even got to date, we met at some parents friend's party. She tried to talk with me, but I was more of a nerdy guy and didn't give her much attention, but I think she liked me back then too, and I liked her too, but didn't have the guts to ask for her number.

Now I observe her from time to time in public transport, and I feel like she is watching me, and she is truly watching me, I don't know if she really wants something from me like I really do, or that she just wants to see what have I become after 2 years. Can you guys give me some tips, what can I do in this situation? Thanks you'all!