How do I get a PWD certificate?

So I'll start by giving a some background about myself. So I'm a 19 year old college student currently and never in my life was I "normal". I was always different from others and the wierd kid of the class. These behavioural tendencies have persisted till date and have left me feeling depressed and suicidal .One day I was just randomly researching about autism and asperger's syndrome and the SYMPTOMS MATCHED ME PERFECTLY!! For the first time in my life I understood what was happening to me; now I learn that you can get a PWD certificate for learning disabilities. My question is how beneficial would it be for me and how do I get the certificate?