Inky, I've just extracated myself from a similar situation.
I was doing all of the work and someone else was taking all of the credit.
I went off 'sick' for a few weeks, the whole plece fell apart

It was a huge ego boost to know that the company will fall apart without me.
I'm handing in my notice on Monday, they can stick that in their collective pipes and smoke it
Maybe you should get sick, or take a holiday.