my cat was outside with us last night and he was fine and i brought him in and the next day (today) he was acting really weird and he kept hissing and meowing really weird and hiding behind the TV because he is very sick apparently and i am worried about him and the vet just said to give him no food or water for 12 hours and hes in the basement now and my parents took us to their friends to sleep overnight and im really really worried about him like what if hes dead or throwing up down there

The only thing you can do right now is try to focus on other stuff. I know how stupidly heart-wrenchingly hard that can be, but if you can’t do anything right now, all you can do is listen to the vet and let your parents take care of it and try not to worry. Deal with the problems when you can. I know this might be really impossible to do right now, but try!