Murph
Keymaster
Post count: 918

Well…

You didn’t do anything “wrong”, you just could have done things better.

Your squat is a million miles from where it was a short time ago, BETTER.

It appears that you are losing your brace a little and throwing it onto your back.
I’m guessing that, and the added volume is what did it.

Try some 90/90 breathing between sets and see if it helps next time.

Back pumps tell you that bracing is off, the breathing may help it loosen.

I highly suggest that instead of skipping the remainder of sessions going forward, you just rest a little longer and see what you CAN do.