Well man you like her and she wants that validation and attention you give to her. But she dont need you - she needs ego boost. So she was using you.
You like her but you cant be friends because you like her on another level and its just gona cause you pain and waste of time on wrong girl. Make sure you are not lonely and have friends, hobbies, communication with other attractive girls. You need to live rich so you wont make stupid choices and want tiny bits of attention this girl gives to you.
Doubt kills more dreams than failure ever will