what happens when a boss changes their minds?

My boss is a control freak and can't delegate for jack. I know he has trust issues from previously being let down, but its nothing that I can do. Recently he was going to hand over a large project and send me on a formal training course, saying that he trusted me to do it. Now a few weeks later, there has been a complete U turn, as if nothing was ever said in the first place. I'm so fustrated, and I don't want to loose my job, but I'm so upset over this. I don't know if I should bring it up or how to even. I do understand that there is a lot happening in the company at the moment!