Thankfully our pediatrician had an open appointment this morning. Matthew got a shot which the doctor thought would stop the vomiting in its tracks and we went home with an Rx for more anti-nausea meds and another antibiotic (for yet another ear infection). The pediatrician's best assessment is that Matthew would likely only want liquids for a few days, solids maybe this weekend.
Matthew drank a little water on the way home from the pharmacy and then went straight to nap afterwards. So far, he's held it down which is a big improvement. Hopefully he is on the mend. Poor little man!
4pm post script: Matthew is throwing everything up again, including the dose of anti-nausea meds. Poor kiddo.