Extra fluid in the brain, IF that's what the docs think is going on, can also be discovered by having a scan done of your head, no needles, with a CT scan very easy to do, like a regular X-ray but you're laying down.. But I tell you what, I think you did ENOUGH dizzy-type rides, they can cause people to pass out, you are not the first one. If you were to go out in your front yard and hold your arms out (don't do this) and spin around and around and around, faster and faster, and then suddenly stop and try to walk forward, you would likely fall down and might even pass out cold. It's just the way the balance mechanism in the brain and inner ear work. It works to keep a human being in an upright, comfortable position, and when you go and get on a bunch of carnival rides that turn you all around and around, the balance gets messed up, and automatically the body reacts and puts you down flat on the floor, it's the only way to make "it stop," the dizziness. I hope I've explained this. This is not a particularly hard concept to grasp. If you go in circles long enough, you'll get dizzy. At least you didn't throw up! Ye gads, that would be pretty bad if someone next to you did that!
And as long as nothing else like that happens when you're in your normal environment, I wouldn't worry too much about a CT scan, altho it won't hurt to have it done, just to be sure your head isn't going to fall off. Just don't ride in those carnival things anymore. I got to where I couldn't ride in them because I found them to be scary as heck when I matured. But if you insist on doing those rides, just make up your mind to only do TWO and no more. That's it. If you pass out from just those two, I'd quit doing it altogether. Actually, if anything, you might want to visit an ear nose throat ENT specialist, he can tell you why you passed out, too, from a balance perspective, and he can make sure your inner ear fluid, etc., are normal, which is where the balance mechanism is. But people faint, pass out, fall down for all sorts of reasons, like the sight of blood makes people faint, medicines, heat, and most definitely riding on carnival rides that go round and round will do it.
I pass out during daily activities, like walking or laying down. I get dizzy constantly and I don't think it was the ride's fault, I went on two previous to that.
Did he order any scans of your brain for this "extra fluid?" Spinal tap? What? That doesn't sound correct.
First, you should have imaging of your brain/head done.