Period question??( girls only unless you are a doctor or something)?

Okay so there is this dance on February 22.9 just a heads up) I have period cramps right now,, i think... i tried going to the bathroom and didnt help, and i ate food, didnt help, i burped, didnt help, so i dont know what else it would be but my period.... my period isnt supposed to be until the 7th. if i get it now then it will most likely end on thursday(like it always does when it starts on mondays) i counted and i will get my period like 2 days before the dance...i dont want to have my period while dancing... i really want to enjoy that night...what should i do or can do to help...im only 15 by the way...why is my period so early??(i am a virgin) and what should i do about the dance??? Sorry if that was confusing! and please help!