I had a sinuplasty on Sept. 2 and since then have noticed that if I eat meat, any meat, I have stomach aches, nausea, and diarrhea. This happens with fish, poultry, beef. I've been able to stomach sugary things, carbs, fruits and veggies, but even ground beef in spaghetti sauce has caused this problem. I don't know if it's related to surgery (postnasal drip causing problems would cause stomach upset with any foods, right?), but the only other thing I can think of is that I picked something up shortly afterwards. Since this has been going on for several weeks I'm rather concerned. Of course, it could be caused by something else I ate with the meat, it just seems that whenever I eat a dish with meat in it I have problems and whenever I abstain from having meat I'm somewhat okay.
Does anyone know what this could be?

other information:
taking birth control pills for two months
allergies to milk and soy but not meat
work at a church nursery about four hours a week (usually just on weekends) with two year olds and have to change diapers on occasion, but always wear gloves and always wash hands
food has been prepared both at home and at restaurants, on stovetop, in oven, and on the grill. Not all dishes were fried.
my whole family has stomach problems, basically IBS, but as I have said before, I've never had a reaction like this to meat.