advice /support needed.. coming off Venlafaxine to go on Citalopram

[alltoomuchrightnow]

Been on Venlafaxine for 12 years and although it helped with depression, I have bad anxiety and severe nightmares/ night terrors so doctor wants to switch me to Citalopram which she says is the best in her opinion, for anxiety
I've gone down from 250 to 75 on the Venlafaxine so hoping to come off it in a week or two. It's just getting through this time. Feeling dreadful. Awful depression and nothing to support that... crying all the time (even things like adverts on tv.... I've never been like that apart from when I have PMS...which I definitely don't have right now) bursting into tears for no reason etc. Feeling desperate, paranoid, over sensitive, and that's just the mental stuff. Physically - dizzy, often nauseous, exhausted, just feeling 'out of it' like I'm trying to run backwards underwater
Is it going to be worth it?
Any success stories with Citalopram? Worried about having dry mouth as i'm constantly thirsty as it is (am also on thyroxine)