From friend's experiences, Citalopram can be a little rough to adjust to - a close friend went on it after months of miserable depression, and went to a very dark place for a couple of weeks: then came out the other side all bright and energetic, got himself a job and is doing really well. So if it starts to mess with you, don't be afraid to go back to your doc: SSRIs can make things worse, sometimes, before they make them better, and they're not the 'magic bullets' that they were proclaimed as in the 90s. But I'm NOT a doctor, and I think citalopram is easier to deal with than most: certainly, I know two friends who say it saved their lives.
The other thing your post brought to mind: you know yourself and what works for you, but as a general rule - and from personal experience - psychedelics and depression don't go well together. Shrooms are a lot gentler than acid in that respect, but especially when adjusting to an anti-depressant, I'd be very careful about tripping: and search around for info on possible interactions before taking anything while on the citalopram. I think stimulants are also saide to be a pretty bad idea on anti-depressants - in your position, I'd give some thought to taking some straight 'clean time' while the pills do their magic, without throwing other chems into the mix.
My one experience with MXE left me baffled as to what people see in it: just seemed like heavily-cut K to me, without the depth to hole or go anywhere interesting. Maybe mine was just poor-quality, but I'm done with RC's: never did know when to quit with K.
Good luck, man, and listen to your body/brain - anti-depressants work wonders for some, but it's a long way from being an exact science.