What type of injury is this?

Back when I was a kid I was working on my bike and I knew I needed oil to lubricate my bike chain. I was around 8-12 years old. Then I climb this table to get the oil and my shirt got stuck on the nail of the cubboard door. The thing was so old that it fell down and the weight of that pulled me down. After that I had hit my head on the solid garage floor on my left side of my head. During that experience I felt very dizzy, off balance, it was so painful I felt like crying, and blurred vision. I then went upstairs and went to sleep cause I felt really sleepy. The next morning I woke up with a fever and a terrible headache. My eyes became sensitive to light and I had pains in my eye whenever I looked around. Can someone tell me about this? What doctor I should see and what tests are involved? I am typing this message now because back then I am 21 now, but back then I was scared, but it could be the cause of my learning disorders.

I did thought it was a concussion, but I was able to remember things. Although the drop was pretty high and I was really short.

Calling the shots on an injury that old would be nearly impossible. You may well have had a concussion, and from the sounds of it that's highly likely. You were also very frightened and that would have just compounded things as far as pain and the after effects. However, it was likely mild, since you didn't need to see a doctor and seem to have recovered well enough. I doubt highly it is an explaination for learning disorders, since those become apparent much earlier in life and have more to do with the wiring of the brain. That was determined at your conception, during your fetal development, birth and the first few years of your life. Even if you had had a concussion way back then, it has long since healed and likely has left no evidence at all. The brain, like the rest of the body, has some ability to heal itself. A concussion is more like a brain bruise, and bruises heal without a trace. So testing at this point would show nothing and tell very little. It's the history of traumatic head injury that doctors have to use, with a few exceptions. If an injury causes damage to tissue that kills it, or changes the electrical function, that damage can be detected. But it can also be present without any history of head injury at all. Sorry, but if you are looking for explainations, you will have to dig deeper and do more research. The incident you mention isn't really significant enough to do the job.

http://en.wikipedia.org/wiki/Neurology

Sounds like a concussion

See a neurologist.