Nobody is indispensible, don't get sucked into believing you are.
ALWAYS look out for number one. If I was in your position I would be sourcing a new position immediately. if only then once it has been offered to you, you can go to your current employer and strongly request clarification on your position, knowing in the back of your mind that you have something else to move onto should they not play ball. I suspect what your doing at the moment is tiptoeing around hoping that everything is getting to be fine, but unfortunately, you can't pay the mortgage with hope, I've tried