If you only had simple fasting sugar blood tests, we don’t really know for sure what happens when you take in a lot of sugar. Maybe your blood sugar spikes more an usual, or your insulin levels are a little screwy. But, most likely you are completely normal. You might have some sort of wiring in your brain that causes you to be nauseas, or possibly the lining of your stomach is sensitive to sweets. I sometimes get pain in my stomach after a lot of sugar, my stomach feels irritated and inflammed.