Jump lesson with a quindrille (?)

I was fortunate enough to have two lessons with John this week; one dressage and one jump.  It was pretty warm today, and warm up was like riding a hunk of concrete.  Not only could I not get Charlie to bend, but he was essentially utterly non-responsive to my leg as well and heavy on my hand.
John had us do work on a circle, with a bend to the outside, make the circle smaller, bend to the inside while keeping everything else the same, and then leg yield back out.  What this does is get Charlie bending around my leg, and then lifting through his shoulders, without just going around the ring fighting with him.  Charlie and I are both stubborn, I think.
But jumping felt the same - it was like riding a downhill sled with no gas in it towards each fence.  John had an oxer with a left turn to a brick wall with a right turn back to the oxer.  I rode him to each fence whomping my legs on and off.  I was pouring sweat and panting, but it felt like I was riding a sack of potatoes.  I don't know if it was the heat or what.
Then we added in the row of five fences with a single stride between each.  These were a bit more interesting because the first couple were a little bumpy, but the last two were always great regardless of how the first two started.  (the one in the middle was just the middle)  John said I was looking too long at the first fence, but sometimes I would also get us on a bit of an angle, but Charlie the champ would get us through anyway.  The last two were really nice - he would round up and it just felt correct.
We did this a couple directions, and he finally whacked the brick wall oxer pretty good, and after that, he was a little less casual about picking up his own legs.
For the lead change, John says I get the front pretty consistently if I remember to turn my head the way I want to go.  The back isn't changing, and John says to try to remember to put my outside leg on.  As I type this, I'm pretty sure I'm putting my inside leg on, so I'll have to try to watch that next time.
I was also riding with my short crop, after months and months of riding with the super long crop.  I hated it, so it was good to practice with John because I probably won't jump again before the show (fingers crossed we make it to this one).
It is supposed to be 101 next Saturday on cross country day.
I put standing wraps on Charlie when we got back to the barn, but I got too anxious about them sagging, him getting tangled in them, and then panicking and killing himself in the night, so we went back out and took them off.  They were on for about four hours, but I didn't really see any difference.
John says for the heat, give electrolytes and cut the warm up in about half.  (15 minutes instead of 30)  I figure we also won't worry so much about making the time cross country because I don't want to fry him for show jumping.
It was a good lesson because I'd way rather ride with John in the heat before I ride in the show at the heat, but it was also kind of frustrating because I just didn't feel like I had him going.
John also said to keep his head up more.  He said Charlie was actually coming into the jump ok, but I'd let his head drop.  I need to follow up with him on that one.  I thought I understood it at the time but now that I'm writing it, I'm not sure I do.  He also wanted to know where my list of questions was, which was hilarious.  If I hadn't had such an incredibly terrible bad start to the day, I probably would have had one, but I was wiped out and just grateful to be riding outside in the sun and not at work.
John reminded me he doesn't like to jump them unless they've done dressage the day before, which I try to do, but I had a meeting last night and there wasn't any way to squeeze in a ride too.