I need some mental help, this thing follows me in my entire life and I don't have the courage to say this to a professional

.>5 year old me
>get out the bath naked
>just lies on the couch while looking at the roof
>2 year old brother
>comes out of nowhere and bites my dick
>I feel a strange tingly feeling for 6 seconds and doo nothing
>don't have any idea of what is happening
>he bites me
>i scream in pain
>never talk about it with no one for the rest of my life

I don't know what to do, i feel fucking bad all the time and i think he doesn't even remember it.