Anyone ever just... lose your swing mid round?

I just make sure my tempo is good. I'll try to feel the way I want to swing the club in my practice swing then try to execute it. Notice I said FEEL not think. Thinking will kill your game on the course.

It happens every round to me and most of driving range practices.

I appreciate the other posters' tips. I need to keep fortified water and a snack with me.

When this happens my woods leave me first. Not much for me to do but work my way back to the longest club that I CAN hit. The last round it was my 31 degree 6 iron. Used it off the tee and all approach shots at 120 yards or over for the rest of the round. Then I just make up the difference with a shorter shot to the green.

I prefer a 9 hole round. I really get too tired toward the end of a full 18 hole round.

Vin sounds like to need to find a fitness coach, last year i missed Q school final stage because I was soooooooo tired i couldn't hit it , ran out of gas, I have been training with a TPI fitness coach and ready to give it a try again.  just something to think about, fitness is very important, yes even in GOLF

I've found a very simple alignment/ swing thought that works for me if the game goes south.  Once I commit to the target I align my club to noon and my body to 11 O'clock.  I focus on visualizing my shot, grip lighter than normal, pull my take away slower, and then think "swing to 1 O'clock".  More times that not it produces that little draw that I love to hit.  It's also helped for first tee jitters and pressure packed drives (the tee ball is the worst part of my game).  I think getting back to basics and keeping things simple helps when you're swing takes a vacation for a hole or two.