From Kelly's blog:
Place a block or piec of foam up under your foot for support.
If your foot is slipping could also be tight ankle capsule.
Go see a good pt for a little breathing room.
"And for crying out loud. Don't go into the pain cave. I can't stress this enough. Your Totem Animal won't be in there to help you. You'll be on your own. The Pain Cave is for cowards.
Pain is your companion, don't go hide from it."