My 3 year old has recently started peeing in her panties..help!

My three year old daughter has been potty trained since she was two. She has never really had any accidents. Of course the random bed wetting, but lately, she has been peeing in her underwear and just wearing the underwear as if everything was fine. She has also been wetting the bed often. I am not really sure why the sudden change. She does not seem to have any pain while urinating. It does not have a funny smell or color. So I don't think it could be a UTI. I'm just a bit confused because she has never had a problem with stopping what she is doing and going potty or bed wetting. Any ideas? Suggestions?