From what I see it isn't that you are so literal but that you have blocked the ability for suggestion, even to yourself. There, imo, are fears behind your not being able to suppose or project imaginations upon anything and especially tests which evaluate!

Fear.
Perhaps you are afraid the doctors will discover whatever it is that keeps you bound. There's reasons behind all those tests for you... and the doctors are trying to find out why you are dissatisfied with life. They, as well as I, tend to think it is more than "just" your being literal.... for truly if you followed that train of thought for life, you would be the happiest person on earth!

Someone who takes things hour by hour as being what they truly are ("just inkblots") and not worrying about what they might be or what they might turn out to be later in the day... living only in the present where all things are not so bad...eh?

You, my friend, imnshpapo, are hiding yourself, fearful that what you might find might not be likable or appropriate. Believe me, you are who you are...and finding out why you are that way can help you live more enjoyably. The tests do not change who you are.... but can give you direction as to which way to go to change into who you really, literally, want to be.