JP and AussieD bring up a couple good points.
If your mind is saying to shoot you'll definitely jerk the shot. You have to gte your mind out of the game, let the shots break and do everything in your power to not tell yourself "I'm gonna get it....NOW". My best scores, either aggregate or match 3 and/or match 5 have been when I was dead tired, had a little too much fun the night before or when I am able to blank my mind and just watch that front sight while squeezing and counting through six and not worrying that the sights, while aligned, aren't exactly where I want them. When I do that I can post a 238 with a high x count for match 3, or a 595+ match 5.
Now to breathing. You are pretty close to sea level where you're at. The air is nice and thick with O2, enough so that you can shoot 2 maybe even 3 shots between breaths (at least you could in a pinch). If you try that in Albuquerque or Raton you'll find out that it isn't going to work. The O2 is much thinner at altitude and you'll be starving for air after 2 shots. You need to train yourself to breathe for each and every shot at anything farther than 15 yards. Funny thing about that, it will also help your timing. Breathe, front sight and squeeze, front sight and keep squeezing shot breaks, hold trigger to rear and follow the front sight where ever it goes, keep holding trigger to rear back until back on target then let trigger forward (follow through) deep inhale and repeat the whole process 5 more times. It works.
I tend to concentrate on the front sight so hard, especially in the team match, that I will completely shut down and stop breathing. Not holding my breathe, just stop breathing. I know this about myself (took a while to learn it though) and now if I am paired up with someone I haven't shot with before the only thing I need from them besides a time check going into left and right hand, or the ocassional sight adjustment, is a reminder to breath every 10-15 seconds. That keeps me breathing. Funny story; first year for Albuquerque with the NPSC, I'm shooting team with a team mate I have never shot team match with. He asks what I want and I tell him to remind me to breathe, just to breathe. Targets turn and I drop to sitting, first 6 are all x's. Reload and go to prone and put 6 more 10's and x's and go to left hand. Left hand looks good for the first 3 shots then the sights start getting real fuzzy, I get the next 3 off without too much damage. Go to right hand and I am struggling, bad. I manage to get all six off, but it was about the 3rd shot when I realized I was O2 starved. I stopped shooting sucked in oxygen then fired off the last 3 with the last shot on the turn. My partner/coach asks me what happened, because my first 15 shots were all almost x's then i went to h***. I looked at him, shook my head and reminded him that he was supposed to remind me to breathe. It was a bad ugly match 5 with 8's, 7's and at least one zero as I recall, all due to the lack of O2.
You might remember watching us in Austin last year during the match 5, my partner/coach would lean in every so often and talk to me. He was reminding me to breathe, breathe Mike, breathe.
You gotta breathe.