Your situation is the other side of the coin from the girl who sleeps with a guy, hoping to get a relationship out of him.

People here are giving you shit for giving her gifts and shit, and trying to turn that into something more, but they also ignore the fact that she seemed to be happy enough taking everything that you were offering, and just leaving anything past friendship as an unspoken option that's on the table.

Lol you were her slut. You were putting out your time, attention, validation, gifts...she was already getting everything she wanted from you. If she REALLY was concerned about you trying for a relationship, she could have taken it upon herself to make sure that it was clear this was to remain a friendship, but she waited until you expressed further interest before slamming the door on you. The fact that she slammed the door that hard on you makes me think that she was fully aware of what she was doing, and just riding it out for as long as you'd stay in your little friend zone. Once you tried to get out of the friend zone, you had no further use to her because now you got a price on you, and she was getting you for free, before.

Just let it go, man. Just consider this a learning experience.