Struggling with an Eating Disorder and Weight Gain

After seeing my endocrinologist, she told me that my absent menstrual cycle is due to low sex hormones & being underweight. She asked me if I could work on gaining some weight so that my period can be restored. I have been really having a hard time with my eating & all of my negative thoughts around food & my body have gotten worse. I was in recovery for three years & after working with a lady who was obsessed with dieting, I could tell that my anorexia was starting to make a reappearance. Unfortunately, I didn't realize how much of an appearance until seeing my endocrinologist. Now I'm trying to deal with gaining weight & trying to overcome my E.D. by myself (because who can afford anything these days?) I'm so scared, though. I don't know what is considered appropriate & "normal." I want to be able to do this myself but I feel so lost :(