Just a word about pyo....the ones that are the most deadly are called a 'closed pyometra'...meaning the infection is sealed in the uterus...nothing comes out..the dog just crashes. When their is fluid leaking you can catch it, and treat it.
I think it is unlikely that Jazzy has a pyo, because her activity, and appetite are still relatively normal. A lot of bitches change a little during estrous...some get more crabby, some more clingy. Then when the added change of bringing in a boy, I would imagine she is just subdued