Why won't this girl leave me alone after rejecting me?

She rejected me and it hurt can't lie but she keeps flirting with me. I was sleeping in class back in the spring semester and I woke up to her staring at me. She said she would text me next semester and wants to catch up. She's had a bf and dumped him in two days. Now wants to catch up when were on campus. What is up with her?
Why won't this girl leave me alone after rejecting me?
Post Opinion