>I quit grains because there was evidence that they are harmful to me,
>but nothing as obvious as that.  It almost seems like I'm more sensitive
>now than when I was eating grains all the time.  Is this possible?  I

this phenomenon is happening with every harmful substances ingested by a
body who showed obvious (but denied and overlooked)  reactions in the 1 st
places. You can see that with smoking or drinking, the 1st presentation to a
toxic substance is rejection by the body thru diverses symptomes.
Then come a phase of "habituation" where the body being invaded by the
substances that it try to eliminate, enter a state of tolerance by changing
the  protection tactic ,  from elimination to storage (organs of elimination
getting overwhelmed by the task).
A safe way to store toxins is to encaste them in fat cells (it is one reason
why the fat body is not willing to loose weight too easely or quickly).
After years of "intoxification"  that way, the level of toxicity becoming
dangerous, the immune system might wake up to get out this state of
"tolerance" thru ,  a viral and bacterial "desintoxification crises", to
come back to a more tolerable level of toxicity. (the foreign genetic
material  of the virus combine with the genetic material of the cells to do
a job that the cells have not been genetically programmed to do, to
eliminate molecules that were not supposed to enter in the 1st place)
The addiction set in, because daily , every night ,when the body try to
eliminate some of the toxins,  it is obliging  thoses molecules to
recirculate thru the blood to be ejected from the system.
The unpleasant symptoms of the morning elimination is best interrupted by
ingesting the "wrong " substance (the morning coffe is the most obvious
ex.). thus you feel better till the next elimination tentative.
Quitting the substance wake up the immune system into an eliminative mood
(whithdrawing symtomes), if you abstain long enough, your body find back its
previous (to the intoxification) level of tolerance(intolerance in fact) and
will react right away to the reintroduction of the substance.
You become more sensitive to what is harmfull .
Rejoice in that one , that is a very good thing to know clearly,  what
belongs to you and what doesn't.
.Becoming numb to feelings is not a good survival skill. Wild animals are
very "sensitive " to what can harm them.
Sorry if i am not clear enough in my writing.
Jean-claude