Doubt it's as serious as it smells.

My buddy Jake had that exact thing happen @evas15 last month in his Civic.

Yeah, I was the same way, always pushing through lunch to get the drywall up faster. Thought I was tough until my knees started making sounds like popcorn and I strained my shoulder reaching for a drill. Had to sit out for three days, which cost way more than any break would have. Now I stop even when I don't feel tired, because that's when you make the dumb mistakes.