sick from coffee

Does anyone else ever get sick from drinking coffee? I don't drink it too terribly often - not every day usually - but today I had "a lot" (but my standards) thanks to lack of sleep and needing to drive for seven hours. I just finished my third mug of it, and now my stomach hurts. That's what happens when I drink a lot of coffee, which is part of why I don't drink a lot of it. Probably my empty stomach doesn't like receiving coffee, and I suspect that the acidity of my stomach is really messed up when it gets too much coffee. Hopefully I will be awake enough from the three cups to remain active for the rest of the evening!