I am watching some videos of the fighters in my gym fighting amateur competitions on facebook. And just by watching them i can feel my heart beating and this rush of nervousness, excitement through my body!!!! Before i spar, i also feel this way!!! It's like my heart's going to jump out!!!
Youth and inexperience, worrying about how you'll do and how you'll look in there, not wanting to embarrass yourself all come into play. It is normal to be a bit nervous prior to climbing into the ring. The more you do it, the more comfortable you will become. Just think, if your heart is about to jump out your chest just getting ready to spar, how's it going to be just before you climb into the ring for your first real fight. Get lots of sparring done and use that nervous energy to your advantage. If you don't, you'll likely gas out early.
Had this for a while leading up to my first fight. I'd use it, I'd focus on it as I was heading to the gym or wrapping my hands or warming up get ready to spar. I'd get myself as worked up and nervous as possible, then as I stepped in the ring or started hitting the pads or what ever, I'd blank it all out, focus on my breathing and slow everything down. Worked a treat. By the time I was walking out to the ring on fight night I was totally blank.