I played in my very first OTB tournament last night. It wasn't a large event. There were 18 people there. It was swiss format. I had a by right before that round. I got crushed by far superior players otherwise.
This guy was better than me. He caught me with an opening trap early on and won a rook. I was able to eventually get his queen for a rook. I was down 18-19. He had a far superior position with 2 rooks and a knight. He was going in for the kill and made a blunder with his knight alowing me to skewer his two rooks with a bishop. If he would have moved his knight another direction, I would have lost.
Moral of the story: Don't beat yourself up being down in material early on, just look harder for tactics. The other guy will make a mistake even if they're a better player than you. If you can recognize the mistake and take advantage of it, you may actually pull a win!
Unfortunately, that was not a game I kept notation of. I kept notation for the first 3 rounds and it was too distracting.