Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner. If you would still like assistance, can you tell me:
How old is your cat?
How long has he had these signs?
Can he keep water down?
Are his gums pink or pale/white?
If you press on his belly, does he have any tensing or pain?
Could he have eaten something he should not have (ie bones, toys, string, tinsel, plants, toxins)?