Why am I losing my intelligence? Please help.

About 6 – 8 weeks ago I began to notice that I was having problems with cognition. It was becoming hard for me to remember tasks I needed to do; I started having difficulty describing abstract concepts, explaining my beliefs; I started having trouble learning new information, such as new information from school; began to feel overwhelmed by all the information that a person has to process every day; started forgetting words (e.g. one day in school I forgot the word “microscope”); I started avoiding conversations with people because it was too difficult; it’s taking me much longer to solve problems such as maths problems; and worst of all I lost much of my ability to appreciate beauty (music and people), and don’t feel emotional anymore.

I’m decaying into some sort of malfunctioning sludge. I don’t want to live this way, sluggishly and dully passing through life, not thinking properly, and not enjoying anything.

When I was a child (2 years old) I had encephalitis. I’m wondering if this has anything to do with it.

I hope it doesn’t seem like I’m complaining; I really need your help.