I had a migraine make me throw up once in college. I woke up that day feeling perfectly fine, got through my first class without issue, but it very suddenly hit me shortly into my second class. I vividly remember it because the professor was actually discussing test scores, which I did well on, but she was basically explaining the grading and said something like "if you scored under X on this test you might as well leave now, because you're not passing this class."

Roughly 2 minutes later I suddenly jumped up and dashed out the room because I could feel the puke coming. Most of the class assumed I'd failed and quit and was very surprised to see me return later that week.