Ducky,
Sounds like fear of fear. That blank feeling any way. The over analysing may be related. Do I feel that way? Not any more, but I used to, I still get close but seldom cross over into that state and when I do it is mild enough that it doesn't qualify.
I'd say you are scared to let your guard down or panic will rush in, but it already has and although it is annoying you it is not going to kill you. So just let it happen and get it over with and use the opportunity to build something positive on the experience. You might find that it is actually less painful than what you are feeling right now. It is also a good time to work on your relaxation and coping skills.
It could be the change of medication, but it doesn't sound like it unless what you have reduced was a benzo in which case it should have shown up sooner, but maybe not.
Actually your brain is functioning, just a little too well, blocking what you don't know for sure you should be afraid of. It won't stop this till you look at what is triggering it and realize it is harmless. Even if it doesn't feel harmless, it is. If that doesn't work then you need to take an anti anxiety to clear the slate so you can start over again. This is what Ativan was meant for.
Short term use to clear the fog so you can think straight. I don't like the drug because of its possibility of abuse but it does work if used right. I won't use it, but I will use its older cousin Valium.
Here for you,
Davit.