It seems like you are suffering from "CUSHING'S SYNDROME"
Following are the signs and symptoms for the syndrome
a) Extreme weight gain (MOON FACE , OVAL FAT DEPOSITION AROUND FACE)
b) Moodiness, irritability, or depression
c) Muscle and bone weakness
g) Immune suppression
h) Sleep disturbances
i) skin pigmentation / dark discoloration patch
What is the wrong with body in "CUSHING'S SYNDROME"
Their is problem with production of excess hormones. (chemical that is release by brain to send message to other organs)
imbalance will lead to all problems mention above.
Here is what he/she will do
1) Do physical exam
2) will do hormone level test in blood
3) may ask MRI-BRAIN to pinpoint the source of problem
4) may ask ultrasound
of abdomen to check ADRENAL GLANDS
located above kidney
5) Treatment is mostly done by small surgery / if not want to go with surgery some medication will be given to take care of access of hormone production.
Hope it helps.