Hey!
Your "paranoia" is if you ask me a normal thing. I had exactly the same feeling the first couple of times I used SPD's.
As lot of things it is a case of getting used to. I tried to speed up this proces by twisting my ankle everytime before a stoplight a fast left/right corner, go so on. So you get a automatic reaction when something happens (I conditioned myself to shiftdown from my 53 to 39 and unclick the pedals at a stoplight. I don't even think about it anymore now when i am doing it, but when it was new i tried to keep my mind to it.)
After a couple of times it is a second nature to you.
Enojoy the Pedals!!!
Kees