Dory's Fist and general Help

I made a Doryani's Fister following a youtube guide, and made some adjustments since VP moved.

In the vid it says like 2mil DPS, if im pickin up like 3 nodes of multi-crit, my dps only goes up like 1k. So, getting that super high dps seems really far out. i have 33crit chance, and only like 224 multi.

AND, Im weak as hell and its annoying. im only at like half of the HP in the guide.

Pointers?