This is answered in another posting.
I am very sorry for your loss!
I will not not be able to give you a definitive answer, since only a post-mortum would be able to acomplish that, but I do have ideas.
When pets die they lose the holding capacity of all the sphincters in their bodies (Sphincters are like faucets that are controlled by nerves and muscles. They open and close). That means that their anal sphincter which holds in the feces relaxes, so poop is released, as well as stomach spincter, so they vomit. This could also happen with urine, when the urinary sphincter relaxes.
Glassy eyes can mean dehydration, and since her extremities were swollen the liquid in her body was not being held within vessels. So, although she may have been drinking adequately, the body was unable to distribute the fluids to the necessary organs, like the eyes and the brain. Without enough nutrients, such as water, the brain will not function correctly, thus her hearing could have been off, or she could have been a bit "out of it".
The body would undergo these kinds of changes from a variety of diseases such as: heart disease, septicemia (systemic infection), and kidney disease. Systemic infection can be caused by any serious infection, such as pyometra (infection of the uterus). Pyometra is a possibility since she was not spayed, and her vagina was swollen.
Kidney disease is also possibility. If her kidneys had failed, they lose the capacity to keep blood proteins in the body and they are lost in the urine which causes the blood to become dilute and pool in extremities (swollen legs, vagina, etc).
I hope this helps! Please post again if you require more information.