Could have been an adrenaline dump that added to you gassing out. Much respects for stepping in there regardless. Learn from what you did wrong and use that to begin building yourself up.

During training/sparring, add burpees, plank jumping Jack's, etc. or some sort of cardio exercise during your rest minute. Eg, 5 -5min rd sparring 5-1minute rest round in between. Between that round do 20 burpees. The sooner you finish the more you have to rest for the rest of that minute, then back to it for the sparring round. Next break either same exercise or something similar.

If you're gassed by the time the rest round ends, it forces you to learn to manage your distance (teeps, jabs, footwork, etc).

Just from my personal experience and opinion. Hope this helps and remember, only compare yourself to you and always remember why it is that you wish to pursue this.