Ouch! Your kitty needs to go to an emergency vet ASAP!!! His tail may be broken or dislocated, and he is in obvious discomfort. Beside the fact that he is in pain, cats with broken or dislocated tails are unable to defecate or urinate because of the position they need to get into (and the positions their tails need to be in ) when they posture. If he is not able to clear toxins from his system by having a bowel movement or by passing urine, he could become septic and die. Please see the following website for more information on cats with broken tails.
It is extremely dangerous for cats to go longer than 12 hours without food as the liver will start to shut down without nutritional support. It is imperative that you have your kitty seen at the earliest indication of illness or injury to prevent a grievous and dangerous decline. You will always save yourself alot of money and your kitty alot of discomfort by having him seen earlier rather than later. You may have bought your kitty some lenghty and intensive hospitalization, surgical amputation of his tail, and i.v. fluid therapy by waiting to have him seen. There are no safe over the counter medicaitons to make him feel better, and I am afraid that he will die soon if not seen. Please take him in tonight so that he can start to feel better. Please let me know if I can be of further assistance. Best of luck with your kitty.