I behave like an autistic... look like one too, except I have a small head, only 21 inch in circumference... anyone here had similar problems? how did you solve them?
People with autism don't have physical deformities that are inherently linked to their condition like people with down syndrome do, so head size isn't really related to it in any way. Phrenology is basically nonsense and head size doesn't seem to have any links to intelligence, abilities, or mental health. Almost every process you do in your brain uses multiple parts of the brain coordinating so you can't really point to one region and say "this is where x happens", just "this is where the visual (or auditory or tactile) part of doing x happens". I didn't read the whole thread so I don't know what part of the world you're from (sorry, feeling lazy and spaced out right now), but have you seen a well-trained professional?
Anyway, even if you are autistic, don't worry, most of the symptoms can be greatly reduced, either with medication, therapy, or practice socializing. Watch out for pseudoscience, tho. Here's the website of the
Autism Science Foundation, and they have a list of treatments that some quacks suggest that do not work at all and everyone should avoid.
I have a mental health field degree, but I can't give diagnoses (and wouldn't give one online if I could). But if you need help finding a reputable mental health professional who could evaluate and assist you, inbox me. Even if you don't have autism, seeing a professional might help you deal with your feelings of despair and loss of purpose you mentioned in your original post.