Hello there. My name isXXXXX and I am very sorry to hear that Micky is not feeling well. The first thing I worry about is that he ate something he wasn't suppose to such as a string, a hair tie, a bread tie, or anything string like etc. . . young cats and even old cats are notorious for eating stringy things that can cause some major stomach upset. It also could be as simple as just a virus he picked up that has caused the vomiting and he just needs a little help over the hump to feel better. So absolutely taking him to the vet tomorrow for a thorough exam and possible x rays is the best. Then depending what is found he can receive and injection of medications that will stop him from vomiting. he can also have some fluids given to him to keep him hydrated until he is feeling better. He most likely is shivering because of the stomach discomfort and pain and not feeling well. That is good he is drinking a bit so he is not completely dehydrated. All litters are considered non toxic as long as they do not eat large amounts. If they eat large amounts then its a quantity problem instead of a toxic problem. most cats do not do this. that is more of a problem with dogs eating out of the litter box. So tonight keep him warm and quiet, keep water close by and call your vet first thing in the morning. They quicker he is seen the better chances of getting him over the hump and feeling better faster. I hope that makes sense and i hope that helps. Cats are very sensitive so I would not give him any over the counter medications tonight. At this point and time nothing would be considered safe for cats. Please let me know if you have any additional questions or concerns. I would be happy to help! Please do not forget to rate my response so I receive credit for my time. Thank you!