My 4 month old kitten had never vomited before until two days ago. He vomited twice two nights ago and once last night. All three times the vomit looked like brown mush (his food). I checked his poop for worms this morning and didn’t see anything, and his poop looks normal. He is acting completely fine - playful, hungry, thirsty. I slowly switched his dry food almost three weeks ago and he never had a bad reaction to his new food. I’m not sure what the problem could be. Can anyone help?