M.C.
Hi B., I am sorry to hear that you are going through this. I know first hand how frustrating it can be, for both my (then) 8 year old daughter and for myself. She was completely potty trained and for some reason, out of the blue, she just started wetting her bed.
I have done everything that I could think of to try to get her to stop. I would stop letting her drink anything an hour before bedtime... didnt work. I would just give her pull ups and hope that she would stop... didn't work. I know that there is a sensor thing that you can get that will start to beep when the slightest bit of moisture is detected, but I didn't want to wake up my whole house. I even took her to the doctor just to be told that she would outgrow it, as her father had issues with wetting the bed when he was young.
Last year I took her to a Urologist and they gave me some very helpful information. First of all, something that I was unware of, is that anything with red dye in it is a bladder irritant so we were instructed to stay away from anything red (Hawaiian Punch, Cereal, juice, jello, etc). We were also instructed to do "fluid shifting". My daughter will take a water bottle to school and have to drink as much water as she could between the time she woke up and 3pm. Then 4-6 oz at dinner, and nothing after that- being watchful that she didn't eat anything after dinner that could be turned into a liquid (jello, ice cream, popcicle, etc). It took a few days, but eventually her bladder did get retrained. She does still wear a pull up for 'just in case', but it does seem to help.
I wish you the best of luck! Send me an email if you would like to talk more!