What Causes Erratic Sleep Patterns And Nausea?

My granddaughter is 20 years old and has the following symptoms: Erratic sleep patterns (inability to fall asleep at night), nauseous everytime she tries to eat something, weight down to 95 lbs from a healthy 110, weakness and pain in legs going up and down stairs. She has dealt with insomnia since early childhood, is anxious and possibly depressed. She is frightened by her loss of appetite, almost constant nausea, and does not know how to improve her situation. I am at a loss as to what to advise her to try. Bought some Ensure, and she was able to drink that and keep it down.