What's wrong with my bird?

I think he puked and he's got this stuff on his head, its gooey and it look like snot or something. He tried to shake it off so I got on his head. Also, he looks like he's bigger than usual, like when they get fluffy to sleep but hes not sleeping or anything. also his eyes are slightly closed and he's kinda slow.
Is something wrong with his diet? hes not old so it doesnt have to do with that.
I'm scared, is he ok? Should I feed him something special?

Hi,

These are signs of a sick bird. If your bird is sick or injured please take it to an AVIAN VET.

- Puffed-up feathers. Birds fluff up their feathers to keep warm, and also when they relax for sleep ... and also when sick. A bird who sits puffed up much of the day is likely in trouble.

- Tail-bobbing when breathing. Birds who sit there puffed up, bobbing their tails, may be sick.

- Half-closed or closed eye(s) for much of the time. Alert and healthy birds usually have both eyes wide open while awake. If the eyes start closing, and it's not because you're scratching a birdie head and inducing pure birdie joy, the bird might be sick.

- Sleeping excessively. Like people, birds who sleep a lot more than usual may be in trouble.

- Throwing up/getting undigested or half-digested food stuck to the cage in weird places.

- Discolored, undigested, or runny poop.

- Ragged, poorly preened feathers.

- Lack of energy.

Your bird is exhibiting many of these symptoms. Find an exotic or avian vet and get him there ASAP.