Any traumatic situation can trigger an attack of depression
However, the incidence of your uncle's death happened when you were 8 months old. This is too early for anyone to actually feel it, experience the pain, and go into depression.
However, yes, if your mother had depression it is more likely that you can develop it too. Childhood experiences also can predispose to Depression.
You should take care of yourself, seek a Psychiatrist’s help, and take medications if you do not feel fine.
Take a wise decision.
I wish you good health.