I've ended up sick three times, and called in sick once.
1) I ate a Chipotle burrito, proceeded to anaphylax and ended up a patient in my residency's ER. I was working (as a PGY 2) in the medical bay, started having severe shortness of breath, tripoding and wheeze... my co-resident (PGY 3) looked at me, said, "You look terrible... come up front to the shock rooms!" When all was said and done, I'd had 3 rounds of epi, 2L of NS, 60 mg of SoluMedrol, Zantac and Benadryl. An epi drip was sitting at the bedside next to the intubation stuff. I swear to God, I was looking at my attending, who was starting to fondle the ETT, wheezing, "Keep that away from me! I'll be fine! You try to tube me and I'll kill you!"
2) I anaphylaxed again after eating rice and beans at the NICU teaching conference. I told my attending I was going to the ER, stopped by our ER and jabbed an EpiPen in my thigh, then went next door to the adult EC and grabbed steroids, Zantac and Benadryl. Backup was already coming into the NICU to take my call, but I figured I'd already be up all night from the epi and the 'roids, so I might as well take my own call. Dumb, dumb move.
3) I had already been diagnosed with pneumonia and given antibiotics by my actual PCP. Then I developed right sided chest pain, shaking chills and shortness of breath. I couldn't even get up the stairs in my townhouse. I called my boss, called my PCP (who sent me to the ER), called in backup and went to the damn ER. I truly thought I was sick - what ER doc goes to the ER? And that, ladies and gents, was the only time I took a sick day.