He was fine this morning, then I put him in his upstairs cage with some food and left for about 1.5 hours. When I came back he had eaten a little of his food but was quiet and still. He spent most of the day on top of his cage, hardly moving. But alert and watchful.
Late afternoon he came over to me but just sat on me, mostly dozing. He pooped a couple of times, small white, small green, lots of pee. He wouldn't eat or drink.
In the early evening I took him downstairs to his regular cage and he immediately took 3 drinks. Then more a few minutes later, and again a little bit later, but no food.
After about an hour I was looking him over and he vomited up the water. I was scared. But he started moving around a little and I was thinking he might be feeling better. After 10 or 20 minutes he went back for more water. Then came out of his cage and sat on my leg while I was at the computer looking for a vet. Then he vomited the water up again and seemed to feel better again. He started poking around for a few minutes then settled down again. He also pooped while he was on my leg. A little white and a little green, but no pee this time. He then wanted to go back to his cage. He's now sitting quietly on his sleep perch (it's past his bedtime).
I think I have found a bird vet but they don't open until tomorrow morning.
Don't be hesitant to call the veterinary clinic if you have any issues. They are here to help. They can give you advice on how to get him to take the antibiotic. Tips for you to give it to him. I am glad that you have found the problem!