Sick? Coincidence? Or part of what happened Saturday?

Well you can rule out appendix which is good. Could be ovulation, could be constipation, when did you last have a bowel movement? Fever, sore throat, body aches sounds like the Flu. You do not state if while you were at the Urgent Care Clinic if they did any blood tests? If they did and all was normal, chances are it is the Flu. As from where you contacted it, well Flu is a funny virus, some people are 'just' carries have no symptoms, or signs of the Flu, but can and do p it on. Good Luck