Hi. My 82 Year Old Mom Has Been Active And

Hi. My 82 year old mom has been active and healthy. She still works 5 hours a day at a school. For the last 2 weeks something is definitely wrong and her PC Dr. is not really helping. She is on blood pressure meds for years but it seems to be up and down lately. Also she has a loss of appetite and is very lethargic. She has been just laying on the couch with no energy. Today she has diarrhea and vomiting. Any suggestions of what kind of specialist or testing I should ask for??