I've been starved and purging.and finally ate and kept down but body won't stop eating now why?

Emotional hunger?: Your starving and purging most likely has left you malnourished and dehydrated. Such behaviors are suggestive of an eating disorder. Recommend further evaluation with your doctor with referral to mental health professional.

See your pcp: for exam to rule out medical factors for increased appetite and/or food cravings. Also some medications, recreational drugs can increase appetite. All should be reviewed with your doctor, who can then refer you to a mental health professional for treatment for likely eating disorder. I hope this helps. Best wishes.