I am potty training my 21 month old daughter right now and I keep her in panties with plastic pants over top during the day. She was doing really well and telling me she had to go, then she spent a weekend with the grandparents and I sent pull ups because I didn't want my mom to have to be cleaning up if she had an accident. Well she totally regressed and I spent the last week retraining her, spent a whole week of constant accidents but finally on Friday she got back into it and is back on track.

So, if it were me I would not do the pull ups and just keep doing what you are doing. I also take the philosophy of not stressing about it and not making a big deal of it if she has an accident. I just put her on the potty afterwards and remind her that this is where she is supposed to pee. I also give lots of praise when she does go pee in the potty and sometimes offer a chocolate chip as a treat.

Good luck!