Why do i look different?

Okay i think im adopted . My mom is mexican-sicilian and is REALLLLYYYY short with black hair dark brown eyes and is dark skinned . My dad is very tall (used to be a linebacker) has brownish-blonde hair dark blue eyes and is WHITE ! && im about 5'7 pale but tan easy , brownish-blonde hair , && really really light eyes that change from blue to green to gray && my face looks nothing like either of my parents at all . Why do i look so different ?