Inpending Doom Help

Hey guys,

my build is based on this guide: https://poe.ninja/pob/igw

my pob: https://pobb.in/TB0YdYBHo2O4

i don't know what i am doing wrong, but with my gear i should have a lot more damage than him, but i have less damage. i have absolutly no clue what's wrong. maybe someone here has an idea?