(I'm Thirteen)Last Year I Had My Period Heavy For 6months

(I'm thirteen)Last year I had my period heavy for 6months starting sept-jan then I went on the pill and it was gone and then regulated for a bit until April/May and then it was on and off till august. From then(August) to now(December 20) I haven't had it at all what is wrong with me doctors don't know!

Things might be helpful:
I masterbate(every day:()
I'm a strested out person
I'm tired and moody even when I get lots of sleep