J.,
My 2 1/2 year old daughter is doing the same thing. We potty-trained at the beginning of Oct. and she rarely had accidents. Recently she has been completely wetting her pants all day long. I too, think she is stressed. I went out of town with my 7 month old for about 4 days and left her with my husband a couple weeks ago. She stayed dry the whole time I was away but since I got back she started having accidents. Anyway, I have been doing a few things and they seemed to have helped...
1.) We have a sticker chart with 30 spots. Every time she pees or poops on the potty without getting any in her underwear she gets a sticker. When she has filled the entire chart my husband and I will take her to get ice cream.
2.) In the morning I put out an extra pair of dry pants and underwear in her room. If she has an accident I let her know she is responsible for taking care of it. That means, she sits on the potty, washes her hands, takes her wet clothes off and upstairs to the hamper, gets her dry clothes from her room and brings them down to me so I can set them up for her to put on by herself. I am not trying to punish her, but I do emphasize that when she chooses to pee-pee or poopy in her underwear she has to take responsibility for cleaning it up. I also point out that it takes a lot more time to clean up from an accident than to just go in the potty...meaning less time to play. I don't ever raise my voice or act upset, I just keep reminding her that she can't play until she has taken responsibility for her accident.
3.) I set a timer and let her know that when it beeps it's time to go potty. This has really helped cut down on my constant asking if she needs to go and the struggle to get her to try. I set it for different times depending on the time of day since I am pretty familiar with when she might have to go. If she doesn't pee when she tries I set the timer for 15 minutes so that she'll try again 15 minutes later.
We've been doing these things for a few days now and today she was dry all day so it seems to be working.
It is so frustrating, I know, but hang in there. I just keep telling myself this is just a phase.
Good luck!