I brought in a stray cat last week. She isn't too skinny, but is small in general. I was petting her last Tuesday and felt kittens moving around in her tummy. Last night she threw up twice, and was having visible contractions, spaced far apart. She would cry out when the contraction hit. Tonight she is still having contractions(a little closer together), only cries out on some of them. She has thrown up once about 10 minutes ago. She isn't eating but is drinking and using the litter box normally, and is sleeping for the most part.. The issue is she is not producing any kittens. I'm worried, but I also tend to be a worry-wart. What do you think? Any insight would be helpful