Damn, I know how that feels... Used to get it doing sit-ups during basketball conditioning all the time.. One more thing for me to look forward to in OCS then. You just kept pushing huh?
Best lesson to learn beforehand: You ALWAYS keep pushing. Even 10 minutes after you thought you couldn't go any more, be prepared to go another 30.
Ah....OCS. "It doesn't stop candidates! It doesn't fucking stop!!"