How to stop becoming obsessed with a celebrity?

It will eventually pass. No matter what you do you will eventually stop feeling this way for her. But since you know you have the problem and you want to stop as soon as possible you should just STOP. Just stop looking up her videos on YouTube and stop watching her movies and stop tweeting her. Delete her or delete your account altogether. You have to distract yourself with something real. Start hanging with your friends more. You are young and should be having fun before you get thrown into the real world of working and responsibility. Spend all the time you can with your friends because they aren't going to be there forever. Instead of craving her movies pick a different theme, like horror or comedy. Watch some scary movies or some family guy or something, play some basketball or go bowling or something. Just distract yourself and before you know it she'll just be some actress you used to have a silly crush on. I know what it feels like because I had a huge crush on Johnny Depp but now I understand he's just a pretty face on the TV and it doesn't hurt me to watch him because I have a real family and friends. I promise it doesn't last forever. Good luck.