Eve is sick

On Friday, Eve was sent home from school because she threw up most of her feed and had a low grade fever (more on that later).  For the rest of the day, I slowly gave her a few more ounces of formula and she did fine.  Saturday, I got in four feeds and did them slowly, but she was fine.  Today, I got in her morning feed and that was it.  When I tried to give her the next feed, she immediately started gagging.  I tried to push through just a very little bit at a time, but I stopped after about an ounce.  I called the on call nurse through the pediatric palliative care program and she said to try to give 2 oz of formula very slowly and see if she keeps it down.  We put Eve down for a nap first.  I woke her at 3pm and we tried to give her the little bit of formula slowly, but she started retching and we only got an ounce in.  I called the nurse again and she came over.  She checked Eve's vitals and listened to her stomach and bowels.  Eve continued retching all afternoon even though she wasn't being given anything.  She never actually vomited, but that's probably because there was nothing left in her stomach (the nurse checked by pulling out the stomach contents through the tube). 

So, when Seamus went to bed, we gave Eve about 10ml of pedialyte with her Valium.  After about 25 minute, we put her to bed.  She so far has kept it down (it's only 2 tsp) and has been pretty quiet in her bed.  The nurse called the on-call pediatrician who said that if Eve started vomiting bile or just vomiting a few times, or if she has stomach pains that we need to take her to the ER.  If we weren't able to get in a decent amount of pedialyte (we weren't) we need to call the office first thing in the morning and have her seen by a doctor.  So, that's what we are going to do.  I'm cautiously optimistic that tonight will go somewhat smoothly, but I have some things together in case I need to make an ER trip. 
I'm worried and scared.  I don't know if this is a virus or further decline in functioning.  I need to focus on the problem at hand and stop letting my mind jump to future problems.