Concerned. (Kind Of Long)

DD was almost completely potty trained, we had her in big girl undies during the day with almost no accidents and pull ups at night, which she was waking us up to tell us she ahd to go in the night.  We thought everything was dandy.  About 3 weeks ago she went and stayed at my ex husband's mom's for a couple of days (we've since decided to cease visits there for other issues), since she has been back we've been having major potty training issues.  She started having accidents constantly during the day, stopped telling us at all when she had an accident, and has been hiding her accident pull ups and panties. 

This morning was really bad though, I noticed she'd changed her panties and asked what she did with her previous pair, she lied and said they were the one she had already had on (she's 3).  So I got up and went in to her room, found a wet spot on the floor and the panties by her bookshelf.  DH picked her up and sat with her on his lap while he asked her about it.  She literally started screaming and crying.  She thought she was going to get in trouble for having the accident, so she didn't tell.  DH really freaked out about this.  DD and SS have never gotten in trouble here for having accidents, we just explain to them they need to try to let us know they have to go potty or they need to tell us if they have an accident.  We refuse to punish them for having an accident, it happens, and punishing them for it can make them afraid.

I mentioned her grandmother to DH (not realizing she was back in ear shot), as soon as I said it she started bawling again, she started yelling at me " No I don't want to go there!!!"  I calmly explained she didn't have to go there and that we weren't taking her there.

This really concerns me though, usually she hears this grandma's name and she's begging to go over there (she's been spoiled rotten there) and then suddenly she's terrified to even go over there.  We just aren't certain what to do now.  I've said my piece with this woman, or so I thought before all of this hit.  We've stopped visits because we're expecting in March and we've gotten DD so excited about the baby, and then she'd go there and come back not wanting the baby to come (we didn't have this issue with her going to her BF's Dad's and Step Moms), amongst a few other issues with her in the last few months. 

Anyways, I'm just trying to figure out how to get DD back on track, to stop hiding her pull ups, panties, and accidents, and to find a way to get rid of this fear that she is going to get in trouble for having an accident.