Venlafaxine seems to be one of the worst SNRIs/SSRIs wrt discontinuation syndrome. Except for the nausea, I had the same experiences when quitting cold turkey. The most problematic symptom for me were the "electric shocks" when moving my eyes or head to fast.
For me, getting off venlafaxine was way harder than quitting tilidine, tramadol or the z-drugs.