Not sure why I am even on this earth

All my life I have felt like an outsider. Like everyone got a handbook on what to do, what to say, how to dress, etc...but somehow I never got mine. Everything has always been SO hard, even simple things like taking a shower can be monumental for me. Growing up my Mom used to tell me that I was ruining her life, and my sister only wanted me around in very limited quantities. Both of them gave me an inferiority complex which has haunted me my entire life. My Dad was the only one that seemed to really love me, care about me, and enjoyed my company. Nonetheless, I never felt like I quite fit in. My Mom and sister were/are intellectuals like my Dad, whereas I was just merely average. I loved tennis and celebrities, whereas they were more interested in Dostoevsky and scholars.