Update: after weeks of grief and processing the whole thing, since yesterday I think that I've finally got over my crush.
Part of it was because of me taking a look at dating apps and realizing that the sea is full of fishes, but most of it was because of a friend of mine. I vented to her about the whole thing and she's a "voice of reason" type of person, so when I told her everything she made me realize how fucked up it was. When she called that girl "manipulative", it's like she turned on a switch in my head and everything made sense.
I realized that she was just a selfish piece of shit who manipulated me the whole time and possibly even told me fabricated stories. I deserve better and I can do better. So what if she's cute? I can just find another cute girl, one that's not an asshole. Fuck giving those people the power to affect your mood and your days, they don't deserve it. I'll spend some time with myself, my family and my friends since I really don't want to have any other girls in my mind right now, and I'll be good as new.
Thanks to the anons who gave me advice, it was useful.