I've been through this recently, if you have the chance sort it out by doing a few simple things, if you really like her but you arent sure wether the feeling is mutual then fuck it, try it. HOWEVER, if they are a friend and always have been a friend its best to just talk to them about it, but in a logical way, just explain how you feel, explain you dont want things to change and who knows, she could take it well, but if she takes it wrong then you lose nothing as she obviously isnt a good friend, ive not been able to read this whole thing matey so i dont know what situation your in. IF she has hurt you though, its simple. convince yourself that liking her is nothing but trouble and you know its only gonna make your life worse not better. thus you will eventually see no love and be able to control yourself. Also if your attacking people verbally or physically when they point out flaws then you might wanna reconsider it as obsession because thats not a healthy thing UNLESS you are currently with them in which case its standing up for her honor. i dont know if this will be any help to you mate. but all the best with it. and eventually you will get over it..... you always do 
besides... it's human nature is it not ? unless your a cold hearted bastard lol
besides... it's human nature is it not ? unless your a cold hearted bastard lol