This idea may be totally off but...
wondering if you've had a bad religious experience
like something that's supposed to be "good for you" (medicine/religious belief)
but you're allergic or something.
Also watch what is going on in your life when/if this dream returns.
Seems to me you are being directed to "do something" that's going against your grain.
Also watch your language/thoughts - anything that makes you think/say
"sick to my stomach" or "nauseous" might tip you off to what these dreams are about.
Good Luck to you.