My 62 year old sister had quick onset of vomiting, dizzyness, and diarrhea over the last 72 hours. The vomiting has subsided, but she is still experiencing nausea and severe dizzyness, sweats and chills, and cannot get out of bed to take liquids or barely life her head off the pillow. Could this be vertigo or sever stomach flu? Should she go to the ER?