Excuse me, you just diagnosed me what???

What a busy end to 2013, birthday parties, my daughters wedding, Hosting a family Christmas party. I normaly get depressed during the holidays, but I managed well until the day after Christmas when everything hit me all at once. The stress and anxiety blew me for a loop. My anxiety caused me several chest pains but it also went down my arm so I was concerned. I went to my family doctor and had an Ekg which came back perfectly normal. The pain down my arm is an over worked muscle and I was put on a steroid. The doctor kept asking me if there is something going on she should know about. Besides my wonderful never ending anxiety. There is nothing i could think of but she brought to my attention that i have lost 20lbs since november and my bmi was right on the edge of being underweight. Makes sense i have very little to no appetite and yeah i am thinner. My doctor informed me with so much weight lost over a short time it was considered anorexia. I love food wth i just dont eat if im not hungry.
I have to go see my psychiatrist friday, my family doctor feels its because of my psychiatric meds. Im really hoping and praying that we get this weight loss thing figured out. Most want to lose weight for the new year, i just want to gain it