It sounds like an adrenaline dump to me, I used to get so hyped up that my eyesight would tunnel out, my ears would ring, and my skin would tingle. Once you get used to going hard while staying calm, it gets better. I'm at the point now where sparring gets me no more worked up than hitting a heavy bag, just because I've done it so much.
If you want to work on your endurance, line up 2 or 3 sparring partners, get a trash can. Rotate fresh sparring partners every round for 6-9 rounds, tell them to come at you aggressively, take breaks to puke in trash can. It might not get you in any better shape than typical cardio work, but you'll get used to fighting while tired.