Overcoming these negative emotions takes much more than just your personal efforts. Most of these emotions especially infatuation and crush often comes in puberty and stays till you defeat it and defeat it you must if you want to worship God with a clean heart.
You have to personally hand it over to God? Emotions are not something you can ever fight on your own. Having feelings for someone is not bad in itself but what you do with/about those feelings will weaken or strengthen you. I pray the following steps will help you to overcome such feeling:
a, Try to think less of that person: When such thoughts come, don’t start day-dreaming and creating fantasies about that person. Instead, become active, you can read your bible and pray or sing aloud to God and with time, believe me, such thoughts will subside.
b, Try never to be in close contact with the person: Don’t pay daily visits to the person you’re trying to overcome feeling for or calling him/her every hour of the day, also avoid being in a room alone with him/her. Give as much space as possible because proximity (close contact) builds feelings that won’t help you at all.
c, Try and get busy: The saying that an idle mind is the devil's workshop is so true, fill your mind with the things of God – meditation and communing with Him. So find something to engage yourself in and believe me, with prayers, you'll surely overcome those feelings.
Remain richly blessed..