Fat kid HELP?????????????????????

ive had past anorexia and now i rlly ned to get back into it, i was going dowon , i got to 140 but then i ****** up, i went zooming to 170 i want to get back down tto 140 see wat i lok liek and do wat i need. how can i reach this goal? im 14 5'7 1/2 and i have an apple body shape