My Cat ate a whole bird the other day and is now very ill, what do I do?

About 5 days ago my cat ate a whole entire bird, probably your average wild bird. Then about 2 days after that I noticed she was laying in her bed all day long. She is an outside cat and sleeps in the garage and whenever I come to feed her in the mornings and night she usually hops out of her bed to greet me because she wants food, but this time she didnt… So at first I wasn’t worried but then 2 days passed and she was laying in her bed literally all day and all night and wasnt eating at all. The 3rd day she still wasn’t eating except she was drinking some water. She puked on the 3rd day, just clear liquid. She is 11 years old, but she still hunts and everything, except now she is all wobbly and isn’t balanced and can barely walk. She takes a few steps now and then lays down to take a break. Tonight, still the 3rd night without eating she puked again. Help me please, I’ve had this cat forever and we cant take her to the vet for 2 more days because of new years and everything. Do you know what this might be and if the bird cause anything or if she is just old? Also she has eaten a whole bird before about a few months ago but never got this sick, she was on dry food at that time then we switched to wet food because of the bird messing up her throat or something. please help me, thank you!!