Is it normal that i always feel lonely

basically my problem is that i still can't get over my grandfather's death which occured when i was a five year old as he looked after me when i was a baby and my mother chose my sister a 2 year old over me,a three month old.
Also my parents never loved me..i was forced to move in with them after my grandpa died due to cancer and i had to move to another city..i always remember him and it almost breaks me apart every time..
also my parents and my sister hate me. they want me to be perfect like they are but don't try to understand me and think i am the black sheep of the family and i know that i am not their kind of person
School was always my escape place i was liked by everyone and had many friends..i was very serious about everyone but as soon as school ended everyone seemed to forget me and now i have a trouble calling anyone my friend and have become isolated from the rest of the world.also i got my heart broken once,and he was the only one i had ever trusted after my grandfather's death and am not over him even after 5 years.
my parents think something is wrong with me...i am not sure..is something actually wrong with me..what is the reason for this?