That fever was high, glad it's gone! Stomach bugs are terrible.
Not a doctor, but I worked in an ER so I've seen plenty of stomach virus patients, as well as been the "lucky one" to catch many stomach viruses. Also a health sciences student, so I've learned a few things...
Glad you're going to the ER. They'll probably give you saline (salt water) IV fluids to replace some of the lost electrolytes. Water alone won't do that. Alternate Tylenol and Motrin for the fever. Phenergan or Zofran (they're prescription) for nausea. Rest. It's not like you can (or even want to) do much, anyway.
Even after your visit, you'll probably feel a little better just for having some answers, medicines, and proper fluids, but it can't hurt you to get yourself some pedialyte. The orange color is fruit flavor and it's the best tasting. You can find it at most stores where food is sold, either near the pharmacy or in the baby/toddler section. It has the necessary electrolytes our bodies need for proper hydration. A lot of the muscle pain and fatigue is because we lose so much fluid and those minerals through the vomiting and diarrhea. Just sip it slowly throughout the day to keep hydrating and replenishing what's been lost.
When you do feel like you can eat again and keep something down, start slowly. Stick to light soups (chicken noodle) and plain foods (like toast) until you can keep them down. Anything heavy and/or greasy is liable to upset your stomach again.
Hope you feel much better, soon!!