Poop and pee obsession what to do?

HI everyone, this is my first post here. It's a sensitive (and gross) subject. I feel I should warn you. It's SO difficult to find the time to stop and seek advice from other caregivers when caring for someone with dementia is so overwhelming, 24/7. The woman I take care of is a friend (she lives with me and her best friend of 40 years, so there are three of us). She has moderate dementia. She has forgotten many long-term things, and definitely has virtually no short-term memory now. But most of all, the BIG issue right now... She has become 100% obsessed with peeing and pooping, and everything surrounding it. She's constantly saying: "So full, so full, have to get it out, have to get it out." And, she rubs her stomach quite hard, for hours a day, repeating that over and over. The issue is, she's not full of either. This sometime happens within 60 seconds after she has gone to the bathroom. This is to the point that we had to take away all access to the toilet. She was in the bathroom for hours a day, 20+ times a day total, and was using her fingers to try and pull poop out. Then, she would smear it everywhere, trying to get it off of her hands we're assuming. So now, she is now in pull-up diapers 24/7. They've worked alright for about a month now, except she won't keep her hands out of her diapers, front and back. And last night.... goodness gracious mother to betsy... last night, we didn't hear her get up. She got into the bathroom, took off her diaper and smeared poop EVERYwhere. Walls, toilet, sink, floor. I can't even describe it in words. There are no words to do it justice. But, the smell woke me from sleep all the way at the other end of the hallway. With all of that said, I don't mind cleaning. I change her bed already, 3-5 times a day because she is obsessed with going to the bathroom. It consumes almost every waking minute and has even kept her awake all night long before. We have to limit liquid now because she's obsessed with drinking as much as humanly possible so she can pee and pee and pee again. We can't give her a drink without her guzzling it immediately. She says over and over: "I need to pee. I need to pee. I feel so full of pee." And on the poop side of things (because it's always one or the other). "I have to get it out. So much poop. I'm so full! I have to get it out." She keeps overflowing her diapers because she pushes the pee out as hard as she can when she realizes she has pee inside of her. She's overflowing maximum absorbency pull-up diaper underwear (every brand, including Depends) at least a few times a day. I've tried everything I can think of. We talk to her about it 15+ times a day, trying to get it to "stick", trying to get her to realize that she needs to relax about the bathroom habits. A lot of other things have hit her like a brick lately too. Her sense of humor is almost entirely gone. She talks to herself but now she stares at one point on the wall as if she's talking to someone she can see there. But, she can still speak well, she can read, although signs in her room on the walls don't work. They seem to "blend into the background" within about 48 hours of putting them up. At this point, she can't go into a day program or go out to dinner or the theater, nothing, due to this 24/7 obsession with "feeling like she has to go to the bathroom." I haven't heard of this happening to anyone who is barely moderate. She was mild just 3 months ago, but has gone downhill like a rocket this summer. Please comment if you have any insight on this. We would appreciate it so much. It's becoming very overwhelming. I'm the cook and cleaner in our home and these days, it's all I do: cooking, feeding, cleaning up poop and pee. It's like an alternate reality at this point. I swear I smell it everywhere I go now, even in my sleep. The constant discussion about it is the worst of it. I feel like we can't just not talk to her. She needs social interaction. But, when I do spend time with her in her room, all she talks about is the bathroom, or feeling full and "maybe I need water so I can pee". I'm out of ideas. I just know it's such a health hazard. We have her on camera now, and an alarm on her bedroom door in case she leaves the room. The camera is on two way-audio. So, when we see her put her hands down her diaper, we tell her to stop. Over and over and over, all day long. But, get this... She never, ever does it when one or both of us is in the room with her. Never. She only does it in secret, privately (she forgets about the camera). Sorry this is so long, but I wanted to provide as much info as possible. Thank you.