just wanted to give hugs as it sounds like this is a complex issue and probaly a little rough on everyone. the pee thing sounds completely normal from what i read from others at that age. my daughter was the opposite, she would have pee accidents in the day, but would wake up in the night to say she had to go, but she is a pretty light sleeper and wakes a few times so thats probaly why.
anyway, i def think you should take her to to a gastroentologist. i wouldnt discuss the problem in front of her but it does sound either like a medical(maybe not serious, maybe just has some or at least to rule out anything) or anxiety from it, maybe she had a rough times at some point and now has developed fear which in turn is this vicious cycle. also i saw your a little about me. my mother is bipolar but thankfully now in her 60s seems to being staying on course, at least ill hope. it was a very different story as a preteen. even if they arent present to see it or understand, it could have taken a toll on your children, or even just the complete absence of their dad. it may not be related at all, but she could have some misplaced anxiety over that. if nothing medical is found, just be aware of the possibility. no one understands how devastating mental illness can be until you live it. good luck to you!!!