Hello,You definitely have a sick dog and it's imperative that she get into the vet very soon . I understand you care about her and want this nightmare of sick dog to stop.
It's important to let the vet's receptionist know the symptoms you've given here if the appt.is not right away.Then they may get you in sooner.
As for her feed you know what works for her so it's wise to stay with that.
Consider offering her small amts(2-3 times a day) as opposed to a whole bowl that she gobbles quick.
It also helps to feed her seperately from the other dogs.
Pale Gums can mean anemia which may be suspected due to her regurgitating food often.
Here's a link with that and other diseases that pale gums may be a sign of.
Anemia in Dogs - PetPlace.com
The discharge can be any number of things including urinary tract infection (an opaque discharge) and/or infected uterus .
Vaginitis (inflammation) may be a watery or mucousy discharge.
Problems with bladder sphincter explained here:(scroll half way down) Vaginal Discharge in Dogs - PetPlace.com
The above site also tells you what to watch for.
Sissy needs to only be allowed to "roam" in her own cleaned yard area. Letting dogs wander can really bring trouble home as you know she does eat feces.
Many animals in the wild are not healty and carry disease.
For this reason alone you don't want Sissy traveling anymore.
I hope you get to the vet soon . Since Sissy has stomach issues consider asking the vet for a shot to "jump start" her.
Also ask for her shots (parvo/rabies at the very least) to be updated if need be.
You are in an area where you don't want to take chances so take action to help Sissy by giving her a good sized fenced area.
This may help her not hold her urine if she isn't sleeping in the same place she is having her exercise time in. (be sure & let the vet know about the holding of urine)
A Quick and reasonable way is to use electric fencing.
We have used that here(we live in the woods also) around our chicken area and out of three dogs only one questioned it twice and there were no more questions after that.
You may need to put a strand of wire low but still not low enough for her to get under and one midway,one at the height she cannot jump.
Then you have created a way to keep her in and she will be happy.
This gives you control over where she goes and you then have the ability to keep her yard cleaned and keep her free from eating things she shouldn't (even clean up her own feces for best results)
Why do dogs eat feces is explained here: Why Does My Dog Eat Feces? Pet Columns: Why Does My Dog Eat Feces?
Hope this helps.If so,please click accept and leave feedback ,it really helps my ratings .
Special thanks for your questions .
Have a very good day!
Thankyou & God Bless!