Yeah I know it's lots of meds but when I combine those with loads of supplements it results a fistful of pills in morning, noon and evening. But none of it helps me with my depersonalization/derealization synrome.
I'll discuss it with my psychiatrist but I doubt she will reduce any of meds, probably she'll add some more.
If that's the case, then maybe you need to switch Psychiatrists. Also, find a good therapist. Someone who does Cognitive Behavioral Therapy. If all of these meds are not helping, it would be advisable to look into a different course of treatment. Therapy, switching meds, etc.
Honestly, medications are way overrrated. Yes, they do help; but they can also be a hindrance. Some of those meds, especially anti-depressents like Zoloft and Wellbutrin are known to have serious sexual side effects, like loss of drive, and not being able to orgasm.
Depersonalization Syndrome/Disorder is a beast. It's not well understood, nor are there many effective treatment options. I don't know if this is possible, since you're in Europe, and I'm not sure how it works there, but I'd also suggest trying to find some sort of a research study to see if there's some sort of new treatment that could work better for you, because you sound miserable.
Here's a link on Depersonalization Disorder, as it's known here in The States. I wish you well:
Depersonalization disorder - MayoClinic.com