my congratulations are first in order, as its exciting to be expecting a new baby, but boy the hardships when it comes to older siblings. My son was 4 at the time I was pregnant with baby #2, my 2 yr old daughter, and he had a lot of drama too. He had problems with bedwetting, in fact has to be on some medicine for it, so I really cant say much about that part of reverting back, but he did try many other things. One time someone asked him if he wanted a brother and totally ripped into the person. I had to chew him out for bad manners to an adult, which he burst into tears and we had to go home again. I truly believe he went thru some of my hormonal moments!! lol All joking aside, I did everything I could to make him apart of everything, however when we bought something for the baby, we made sure to get something for him too, and also buy some extra things so later when the baby got presents, we could slip some in for him too. Its not easy being the only child, then have another child thrown in and then as in your situations, be the baby of the family for as long, and now wont be the baby of the family anymore. Consistancy is the best thing now. Keep punishments the same as usual, but also talk to her and try to help her understand her own feelings. I know its hard to be pregnant, hormonal, and understanding all at the time time! He did have a few moments after the baby was born too, but now they are very good friends and play together and have fun together, even though there is 5 yrs between them. When daughter #3 coming, I tried to get my 2 yr old, who was only 1 at the time, involved too, but she could have cared less! We had more problems when the baby came home. Now she has worked out all her problems and plays great with our 9 month old. So, try to stay consistant and keep the schedule/routine the same and eventually all will come together. Good Luck!