Agree with Jenn - the oatmeal reaction sounds like an actual allergy to me, the squash possibly an intolerance. I'd also stay stick with the rice cereal for now (if anything) and wait at least 2 weeks to try anything new. When you do, maybe try a very small amount of something like pears, apple or sweet potato in the morning. I'd suggest doing only 1/2 teaspoon the first morning, 1 teaspoon the second morning and then continue doubling for 5 days - after that you should know if it's a "safe" food.