Putting the feelings into words....
Well, I guess back then alot of soldiers drank as much as possible before a battle to dull the nerves. Unfortunately that's not an option for us as we'd get thrown off site.
I do get nervous though.
Will the guy I'm fighting be better or worse than me (the difference between having a good battle and playing a corpse for an hour - if it's a hot day I like the corpse option) - will he be an idiot and go for head shots, elbow shots, knee shots (you're only meant to hit the torso or upper leg).
Am I actually going to get hurt this time? (1 broken finger, lots of bruises, a couple of broken ribs are my tally so far after 5 years in the game).
Most importantly though is: will it look good for the public, or will it look like some playground fight with lots of pushing and shoving?
Another bit that plays on my mind for the historical battles is will the battle play out as it should do?
At Hastings last year my unit was selected to be the Norman unit that turned and ran when we think that William is dead. A unit of Saxons was meant to give chase (and subsequently get hacked to pieces). They didn't follow so we had to march back up the field (after running 200 metres in full armour) and rejoin and kinda ignore that part of history.
Also, what if the other guy doesn't die when you hit him? That's really annoying! Our group has a 'telling blow' rule. If you felt it and it was a hard enough blow then you're dead. We also have a rule of: If they don't die when you hit them then hit them harder. If they still don't die, then trip them up and jump on them.
Then you've got to remember to keep your shield angled forward at the top slightly to stop a sword sliding up the shield into your face. You've also got to remember not to duck, etc - if someone goes for a chest shot and you duck, at the best you'll lose a couple of teeth.
What if you let your unit down? You die and there's a big hole in the middle of the unit, the unit on your left dies and you don't always realise until you're being stabbed in the back (happened once - our entire unit was left lying in a pile on the battlefield after another unit collapsed and we didn't see it).
The nerves you feel in a big battle is nothing compared to the smaller tournaments though. In a big battle your one person in an army. In a tournament your two people infront of a few hundred people and you'd better make it look good or people won't be interested.
My favourite bit though is after the battle when you get all the kids running over wanting to hold your sword, look at the blood dripping from your knee (generally caused by slipping in mud rather than being hit) and ask you lots of questions.
Lots of fun!