HELP!!!!! My period wont stop and its been going for about 3 weeks. I'm 14 im so scared, i need some answers!!?

I'm 14 and my period started a month ago, up until now its still going, its not spotting, its definately not. I'm so scared, maybe i wont have kids. I've been so weak lately, could it be lack of iron or something? Cuz i dont drink milk. I'm so scared i dont know what to do, i dont want to go to the doctors though because i dont want them to examine my private part, i didnt nkow it was this serious until i read about some serious stuff about the same situation of someone my age. Oh please help me......i'm crying