Abrupt onset of vomiting and diarrhea with fever the majority of times in children is a stomach virus; very common throughout the year. Worrisome signs would be either bloody or dark green vomiting, bloody diarrhea, or persistant vomiting after 24hrs. If she isn't arousable at normally awake times, that would be a concern also. That being said if you see those things she should be seen sooner than later.
Fevers are the bodies natural response to fight infection. There are a lot of myths and fears regarding fevers. Indeed they can be uncomfortable and make children fussy, sleepy, not eat, and achy. They do not cause "brain damage." It is not so much the number of the temp that is important rather than how the child appears. With the advent of modern vaccines, fevers aren't as worrisome as they once were. There are a few exceptions to these rules, however. Any infant younger than 1 month with a fever should be seen, and a temp of 104 in children younger than 3 should prompt a phone call to your childs doctor at the least. Also, any fever over 5 days should be evaluated.
With the stomach bug, being a virus, there is no treatment to cure it. Clear liquids should be given until vomiting has resolved for 6 hrs. Then bland foods such as breads, crackers, bananas, rice, applesauce can be given. If that is kept down, then progression to a normal diet as quickly as possible is recommended. Diarrhea may last for 7-10 days, but over that time her energy level should be returning. Vomiting usually resolves in the first day. I hope she feels better soon.