Hi,
It's very possible that she has not passed all of the ribbon and/or ingested some other things she shouldn't have, at the party. If some of this ribbon has become wrapped around her intestines or bowels, this is very dangerous to her health and may be what's causing the current problem.
Because she's a 'senior' cat, she may be developing an illness like diabetes, or a kidney or thyroid problem, which may be coincidental with the ribbon ingestion. Is she urinating normally?
When a cat doesn't eat for a period of time, this can adversely affect the liver and a condition called hepatic lipidosis may develop. Since she's lethargic, has few stools and is a senior cat, I'd have her seen by the vet ASAP (I know it's a holiday weekend, but try your best). You can try to give her some hairball remedy (Laxatone/Petromalt--available in Petsmart/Petco) which will 'lubricate' the intestinal tract and this may help, but she still needs to see the vet for an x-ray to see the location of any ribbon which may remain and see if her intestines or bowels are being 'strangled'.
Try to get her to eat by watering down some canned cat food and feeding it to her with a dropper--every 15 min. for an hour.
I would try my darndest to have her evaluated by the vet as soon as you can.
Please keep me posted. Thanks!
Cher
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