I'm So Confused

it always seems that a girl ONLY talks to me when she is upset needs someone to talk to or things like that and while she needs me we are hella close but then when she doesnt need me anymore she friend zones me without a explanation and stops talking to me as much as she would and it really hurts to be honest why must you use my niceness and personality to your advantage and let me get to were i think og you as a sister then just change totally up when ive helped you get up gave up sleep at night to be there for you worried myself sick about thought i had a little sister or older sister that i could talk to now but no i always get used for differnet things