The elusive right lead canter

I don't know what was going on today, but we could not pick up the right lead canter to save our lives. Willig was doing gorgeous, beautiful collected canter work, and he has nooooo problem counter cantering, even on a little 10 meter circle. Or when I'm contorted around bending to the outside to "assist" him in picking it up correctly.
Now, of course, there's something actually going on with me (other than what appears to be a total mental riding break down), and somewhere on the right side of my body, I'm doing something that is so strong and powerful that it overrides the aids that I think I'm giving with the left side.
Today's take away is that I am so frustrated. Yesterday we had this decent ride where I finally felt like my heels got the message, and I was so looking forward to today's lesson to show that off, and instead, we could. not. pick. up. the. right. lead.
So I don't really have any takeaways, because all we did was flop around in circles and look like we had no idea what we were doing.
Mike spent a lot of time demonstrating what looked like yoga warrior moves to show me how a horse picks up its leads. He also talked about the bend in my body (not holding the inside leg on him when I'm asking him to pick up the lead), and moving my leg back (sliding it back, not just lifting my heel) to ask for the lead. And then we did this funky trot-walk-trot-walk-canter-trot-walk stuff where Mike changed it every few seconds, so that Willig had to LEAP off my aids and do the transition.
Mike was very satisfied with Willig's canter ability. He said it was basically 2nd level about to do flying changes. I gritted my teeth because it doesn't matter if we can do flying changes if we can't pick up the lead I'm asking for in a 1st level test. Or go past a spot where, horrors, someone raked and there are rake marks in the earth. He even spent extra time with me, and we still just flailed around, and then after he left, I started crying.
I don't know what's going on with me. I think I've hit a wall.