I must chime in on Suz135's behalf, since I believe she has a point... and the condescending attitude of some posters here is very depressing.
I can believe that one's stomach gets accustomed to the food one regularly eats. And I don't find it a ridiculous notion that raw meat might contain bacteria which irritates certain people's stomach but not others.
I had a similar experience in the USA 10 years ago. I wolfed down a plate of chips (sorry, freedom fries...) without realising that in the USA, hog fat is often used for frying. Having been a veggie since '88, this confounded my system, and the next three days of my holiday were wasted while I divided my time between my bed, the toilet and the pharmacy.