How do I know if my toddler has a UTI? Also, potty training regression?

My daughter is mostly potty trained and has been for a couple months. She’s 2 and 3 months. She still doesn’t really tell us when she has to go, but if I take her regularly enough she won’t have any accidents.

But the past 2 days while at her babysitter she has had several accidents, both poop and pee. The babysitter will take her, and then she just doesn’t go. And then 20 minutes later she will pee herself. She doesn’t cry when she pees, or indicate in any way that it hurts. Is it possible she’s avoiding the potty because she has a UTI?

Or perhaps is she regressing? In that case, how do I handle it? Do I put her back in pull-ups?