I've Had Very Bad Diarrhea Over One Week. It Started

I've had very bad diarrhea over one week. It started suddenly. No change in diet, no new medicine, no one in my family is sick. I don't think it's a virus because my husband feels fine. It's like brown water coming out. I'm drinking as much water as I can but the only thing I'm able to eat is dry toast and bananas. Everything else goes right through me. I'm down 8 pounds. I was in the ER last Sunday. All labs, urine specimen, and CT scan were normal. They did not ask for a stool specimen. They sent me home to wait it out. My blood pressure was high that day, 146/76. Yesterday I had it checked again, it was 148/78. This is very unusual for me - I'm on blood pressure meds (hydrocholorthyazinde HCT). I've had occasional dizzy spells and nausea but no vomiting. Fever on the first day was 100.5. no fever since then. my family doctor can't see me until November and told me to go to urgent care. Before I go that route again, what other tests should they be doing?