I'm not the person you replied to, but I was on 350 mg (which is a reasonably high dose). I was on venlafaxine regular release, not the extended release. If I missed a dose I got full on discontinuation effects. When I tapered off it wasn't great, but it wasn't awful.
Some people do report problems even with a very gentle long taper down.
My wife has been on venlafaxine for years, and has been tappering off it for the past year. She has had horrible withdrawl symptoms from missing a single dose, like you describe. Each time the doses town (tapering), she has a rough few weeks.
How long were you on it? Do you have any advice? Thanks.