OMG...been there, glad we've passed that!
I cant remember the name of the hold, but put your baby face down on one arm....your hand should go between its legs...then clasp hands...tummy down on your arms....WALK WALK WALK.
DONT BEAT YOURSELF UP! You are not a bad mommy!
Best advice you will get: GET HELP when it seems like too much. Cry if you need to (if you're not now...you likely will sooner or later).
Good luck, we went through this forever. I felt like the worst mother in the world and I felt like I should never have had her (
)...but you will get through it.