My Aunt Is 50 Years Old And Since Early This

My aunt is 50 years old and since early this morning she has been experiencing dizzy spells at times when she stands up. She stated that a couple of times last night she would close her eyes for a few seconds and when opened, the room would seem to be spinning. She has also been frequenting the bathroom with bowel movements more than usual today. She has been a little "sluggish" today also. She's only had water and a few saltine crackers today. Any ideas.........