Potty training regression (or, "my 3-year-old has started shitting herself about once a freaking hour")

My little girl was potty trained by the time she was two and a half - by about February this year. It took several weeks of chatting and working through feeling-acting logic after Christmas, but the penny finally dropped and the diaper came off, and at the same time she even decided a potty was for babies - she's more in favor of climbing up on a step to a reducer seat on the adults' toilet. She eventually went to daycare with no diaper and had zero accidents from Feb-Jul.Started nursery school this September, she was a bit freaked out by the new circumstances, as were all the new kids, but quickly learned the protocol to go to the bathroom, and after a week there she seemed happy and settled, even running into the classroom on her own with a big smile, and coming home full of the joys of her classroom activities. As far as I know she has not been victim of any bullying problem, and three of the older girls appear to have befriended her, something she's really proud of.Last month she had a poop accident in the class. No biggie. Then two days later she had another two. Then the next week they called me up to come get her because she'd soiled all three changes of clothing we'd sent in.This went on for a week, then she went back to perfect pee and poo behavior, asking the teacher to use the bathroom as required. Now a month later it's started up again. She even stands there pushing, I ask her if she needs a poop, she denies it, then immediately shits her pants. Or I see her start to push so I rush her to the bathroom to put her on the john and she screams blue murder "I don't need a poo poo" but she did and it's too late anyway. She always denies it. It's never a full-size turd these days, just enough to stink and make me have to wipe her and wash her and change and wash her clothing.She's a happy, otherwise well-adjusted and bright kid, with a wicked sense of humor, very loving and affectionate, and she hasn't pissed her pants for months. The shit, however...I am sure it's something to do with the new school but I can't get to the root of what the issue is. I've tried all the techniques I've read online: to make it not a big deal, just change the kid and move on, don't revert to diapers during this phase. And I know it's a phase that will hopefully wear off soon. But she's crapped her pants seven times today so far, I now have shit stuck under my fingernails, and I don't know what to do, so I'm reaching out to ask if anyone has had this problem and has any advice. via /r/Parenting https://ift.tt/2pqAr23