My 3 Year Old Feel Down The Stairs Monday Night.

My 3 year old feel down the stairs Monday night. Tuesday evening she was sick and had a temp. My brother had a sickness bug and she was around him Sunday so I thought it was that. It's now Friday and she has just been sick again, not food yellow ish mucus. Is it normal to have 48hours between being sick. Could this be related to the fall?
Thank you
Sarah