I am very sorry to hear about your girl Pia's abnormal loose stools with mucous.
Has she passed any blood with her stools?
If so the fresher the blood appears the closer the source is to her rectum.
Mucous, loose stools and blood are all nonspecific signs of colitis, which is inflammation of the large intestine.
The important factor in all of this is how your girl feels otherwise.
There is a condition in dogs called hemorrhagic gastroenteritis. These dogs have profuse dark, jelly-clot like, bloody diarrhea. They are very sick dogs, often vomit too, and get dehydrated quickly so they need immediate care. Thus if she seems lethargic and/or is vomiting an emergency veterinary visit is best.
But colitis or inflammation of the large intestine, which causes blood and mucous in the stool, can also be due to stress, a change in diet, parasites, a viral or bacterial infection, inflammatory bowel disease or even a food allergy.
A raw, irritated colon can take a few days to heal. Do you know if she got into anything that may have started all of this?
Her stools should start to firm up and mucous lessen with treatment over the next 2 to 3 days. If not she should be checked by her regular veterinarian. Well worth checking at least a couple fresh stool samples too as parasite eggs/cysts are shed intermittently and they may be picked up on the second sample or third test even if the first is negative.
If you cannot have her examined today then we can try some things at home.
If her appetite is off and her stomach is gurgling she may have some stomach upset and reflux that can go along with her mucoid, loose stools.
To try and settle her stomach today you can try either:
1) Pepcid-ac (famotidine) at a dose of one quarter of a 10mg tablet per 5 to 10 pounds of body weight every 12 hours.
2) Prilosec (omeprazole) at a dose of one quarter of a 20mg tablet per 10 to 20 pounds of body weight every 24 hours.
These will reduce stomach acid and should help if this is related to simple nausea and gastrointestinal irritation. They can be given for several days if necessary.
I would not feed her any food for 12-24 hours after the acid reducers are started. This should help stop gut spasms and restore normal gut motility. Small amounts of water or ice cubes given frequently are fine as she needs fluids after all that she has lost with bloody stools. You can give pedialyte to replace electrolytes too but Gatorade is much too high in sugar which can make her colon irritation worse.
Today even with the fast you can start Kao-pectate at 1/2ml per pound or 1/2 tablespoon per 15 pounds of body weight every 12 hours. This will coat her irritated gastrointestinal tract as well as absorbing bacterial toxins. You can use it for a couple days until her stools start to look normal. You can find kao-pectate at the drug store.
If she has a tense painful abdomen, continues to have diarrhea without any improvement after being on kao pectate for 24 hours, becomes very lethargic, continues vomiting or runs a fever greater than 103.5F then she really must be seen by a veterinarian as soon as possible. Make sure to take a fresh stool sample with you when you go.
After her food fast start a bland diet of 1/3 boiled, lean hamburger (or boiled, white skinless chicken), all fats and juices drained off, mixed with 2/3 boiled, plain white rice. Feed several small meals a day. You might wish to add 1 tablespoon of canned pumpkin to each meal as fiber helps soothe an irritated colon.
Once he feels better (no diarrhea for 48 hours) start mixing in her regular dog food very slowly. Less bland more regular with each day. It should take a week or so to convert her back.
If your pup is vomiting and feeling poorly though it would be best that she see a veterinarian now as anything you give her orally will just come back up worsening her dehydration.
Best of luck with your pup, please let me know if you have any further questions.