This is common with the impending arrival of a new baby and when bubs is here you will likely find it will be more so. Don't let her see that it's bothering you, do what you need to and rest assured it will eventually pass. Some special one on one time is very important now and when the baby comes. I found this with Marisa who was 2.5 at the time of Elijah's birth, she would act like a baby and wet herself, it was very frustrating at times as she would deliberately wee to act like a baby But it's all normal and if we can not make a big deal of it (which I did at first not understanding it) then it will pass quicker...