You have every reason to be concerned.  One time my daughter had a tiny bought of diarrhea in the evening.  We gave her a triple dose, checked temperature gave liquids etc.  and went to sleep.  In the morning she slept in later than usual.  When she finally did get up she stumbled to me and collapsed in my arms.  We gave her the shot immediately.  It was very scary.  All from seemingly minor illness.  Keep a close watch always.  Good luck Julia