I am very sorry to hear that Callie ingested about 20" of ribbon yesterday, vomited a piece of it overnight and is now lethargic and not passing stools.
I am concerned to hear that she is not acting herself, but rather is lethargic, I do think that she is in trouble.
She cannot pass stools if the ribbon is blocking her gastrointestinal tract, and if she is vomiting that will lead to some dehydration, thus she will have less fluids to produce urine.
I suspect that the ribbon has caused at least a partial obstruction, and since she is vomiting she may be to the point that surgery is needed to relieve the obstruction.
If she weren't vomiting there could be some things we could do to try to help her pass the ribbon, but at this point I am afraid anything we give orally will just lead to more vomiting and worsen her dehydration. The more dehydrated she is the less resilient her intestinal walls will be and the more likely we are to see significant damage. Ribbon can act like a hacksaw blade on the walls of the intestine, and if we are not careful she could end up with a hole in her intestinal wall and secondary peritonitis.
I know you were probably hoping for some way to help her at home but at this point she needs hand on veterinary care and possibly surgery.
Please let me know if you have any questions about my recommendation.