Plz help me. I went anorexic a wile ago and my perod stopped den i ate agen & it stated js wen i was gonna sto

Plz help me. My period stopped for like one year after i stopped eating. I started eating again when my mum found out and gained weight to 6 stone 10 lbs. Then i decided to try and lose weight again just as my period decided to restart. I'm so upset and confused cause i want to lose weight badly but i don't want my period to stop again. If i did lose weight would it ever restart? How much weight could i lose without it stopping? I am 5 foot one inch and thirteen years old/. Plz hlp!