Similar experience here. I was 13 I think, playing in the knockout round of a tournament, Select level. The OT format was something like 10 minutes total, dropping by one player every two minutes. I'd played about 5 or 6 minutes out of the 8 minutes leading up to the final 1 vs 1, including almost the whole 2 vs 2. When the coach asked me if I could go, of course I said yes but I was totally gassed. Lost the face-off but kept him in front of me, he came in 1:1 against me, I forced him to the outside and we circled around the net but he just had a little more and got out in front and chipped it over the goalie.
It was one of those unique experiences that you remember. Always regret not giving the ice to one of the fresher guys for even, what, 30 seconds? One skate up and down the ice would have been enough time to recover. It didn't change me in any way though, I still take on too much even when my chances of being successful are small. Might be a fear of letting people down or an overconfidence in my abilities or perhaps just an ego-driven desire to be a hero, I don't know. I usually don't recognize it until afterwards.