My first (?) fall on Duke

I rode with Christa today, and with hindsight, made every mistake I know not to.
First, I hacked Duke Tuesday.  and I was at the Rolling Stones last night, so maybe John didn't ride him Wed.  Ashley told me all the horses were kind of hyper from all the noise with the jump construction and show prep (which I, moronically, said "good" in response).
Then, Christa and I were trying to stay out of Kristie's way, and then looking for John, and then talking, so we didn't do a real warm up.
John had us start with a cross rail, which became a huge vertical.  We didn't do any trot or canter warm up (like he usually does when it's me alone).
Then we did a big sweeping right hand turn vertical to oxer, than a hard left hand roll back 10 meter turn vertical to oxer.  I had a hard time seeing the difference in the two lines.  When you ride the sweeping turn to the oxer, you have more space than when you ride the tight roll back to the oxer.  John said we rode the roll back too tight.
From there, we were supposed to do a vertical to oxer, left hand turn, one stride to two stride (triple), right hand turn, the easy vertical to oxer.
Duke and I fell down on the left hand turn between the oxer and triple.
He was stiff in the bridle and didn't want to bend to the outside, and when it was obvious he was going to motorcycle through the turn, I panicked and instead of counterbending him, tried to open my inside hand.
And instead of fixing it - trotting, bending, turning, scrambling his legs - he decided to fall down.
He scraped his left side up with at least nine sand scrapes, and landed a bit on me.  My right back and left hip and knee are gimpy.
John had us sweep off, get back on, and ride it again, with a trot in between the oxer and left turn to the triple when he refused to get the correct lead (or trot) and then again.  Duke was just stiff and mad and knocked the rails, and got every single lead wrong.  But we did it.
I hurt already.  I feel old, and an ominous foreboding about how long my riding career will actually last if I hurt more and more with every fall.