PT regression

[HappiMom]

My daughter potty trained in November (right on her 2nd birthday) with hardly any accidents. She did awesome. Suddenly she keeps pooping in her underware. She does it every single day. Full poops. I don't understand why she has decided to do this. I feel like at first it was an accident an she couldn't get to the toilet fast enough because she'd finish on the potty. N she has started to hide under the table like she did when she wore diapers. Any advice?

Edited to add: other unusual behaviors lately include her obsession of wanting to be a baby. If you ask her, "do you want to be a big girl or do you want to be a baby?" She will say a baby 100% of the time. One of her old diapers fell out of the closet and she picked it up and hugged it and wanted to wear it. I told her if she keeps pooping in her underware she'd have to wear diapers and she said, "ok!" Not what I wanted to hear. She's all over my breasts again, we weaned 4 months ago, and always asks for a "baby pacifier." I'm also 11 weeks pregnant, and, it may be a coincidence, the behavior started as soon as I got pregnant.