P.M.
Stress does funny things to bladders, and a uti is also worth checking out. Because poop is part of the problem, there's also a possibility that she's constipated, possibly even has an issue with encopresis (google this) where she can't feel a need to poop, but some stool pushes past the blockage and accidental soiling results. This could also push on her bladder, and make accidents harder to avoid.
I think your instincts are sound about the changes and the control issues being contributing factors.
I hope you'll check out the book How to Talk So Kids Will Listen, and Listen So Kids Will Talk. The authors have years of experience teaching parents how to help their children identify and communicate their feelings and needs, and participate in finding their own solutions.
They also teach how parents can effectively establish their own needs and boundaries in a clear, understandable, and respectful way. Much of the book presents situations with good and not-so-good ways of handling them in a clear and easy-to-read cartoon format. Try it; I think you'll like it.