hi i'm a 15 year old virgin.my periods are usually on time and last about 4 or 5 days. my february period was a week late and very light and lasted about a week. again same with my march one. in april my period was a week early and only lasted about 2 days and was light. i just started again yesterday and so far it's very light. i've also been having cramps everyday since february and my legs and back have been hurting. can someone tell me why this could be happening ? thank you