why does my mother call me 'Alex' and not 'Alexander'?

[Alexander]

I was named Alexander. that is my name.

my mother cals me Alex. 'hey Alex' she says 'wash the dishes' etc.

but she gave me the name Alexander but doesn't use it (says Alex instead)

is this subtle psychological behaviour that implies that she does not want me? that she hates me or regrets me? or that she doesn't even want to bother with calling my full name (because I am not worth)