It's too difficult to say. There are so many things that could cause this, along with damaged tendons, joint issues, trauma (breakage of the bone), neurological issues and others. The fact she isn't eating is indicative of pain - the same with not going to the toilet (she probably finds crouching painful). Have you been to a vet about it? If not, you clearly need to.
Tony
Doxies are notorious for having back issues. She may certainly be in pain! I would make an appt to see your Vet ASAP. Please do not let the kids carry her around. Try to keep her quiet and no jumping or stairs.
It's very treatable....The sooner you get her there, the better the outcome.....
She needs to be crated until you get her to the Vet. You can carry her out to potty (Not the kids) & carry her back in, put her in crate.....Don't wait any longer...Let us know what you find out....