Have Cat Questions? Ask a Cat Vet Online.
It sounds like you're seeing a Permethrin/ Pyrethrin toxicity. These are typically due to dog flea products being inadvertently placed on cats. They are toxic to cats. The treatment is with a muscle relaxant called Methocarbamol. You need a vet exam to be prescribed this medication. With more severe cases, we'll treat them in the hospital for the first 12-24 hours.
If your vet is closed, they should refer you to an ER vet in the area. If you don't know where that is, here is a helpful site to locate the nearest ER vet for treatment:
I hope this helps, let me know if you have any other questions.