Why is this embarrassing? Just be cool and objective and seek clarification. You have the emails, no?
If he found someone he likes better, it's whatever. You can't let this stuff phase you. Just learn to seek clear and verifiable validation.
Heck, I have had nurses, back in the days when schedules were written in, erase or cross out my scheduled dates, so that I would come into work on the dates written and presumably approved, only to be sent home or to be called at home, with "Why aren't you here?" Copies of final/approved schedule well in hand, scratching my head. But I caught on to the game. Being young but not apt to be walked all over, I learned to get validation on all final schedule approvals in various ways, especially with the right people. It took extra vigilance on my part, b/c sadly there are just people that play dirty pool. In the digital world, it's easier to verify and to f/u w/ validation. I also learned to check the schedule every day I was on and have my friends notify me on my days off of any changes--and to verify back final schedule copies. That is, you seek clarification with the right people w/ final word on the schedule in writing after the final schedule approval date. Amazingly my surprise changes on the schedule ended, b/c I went the extra mile and sent final copy as if to say, "I am forwarding this copy to you, so that we can agree to my expected dates on the final, authorized scheduled, and that any changes will be made via phone call and written verification." You are not trying to be a j.o. You just don't take such idiotic antics sitting down. If the leadership over the schedule blew it off, I would have gladly tendered my resignation, for this is not acting in good faith. And if there was a tendency to not act in good faith w/ each other on things such as the schedule, if some serious patient/legal/clinical issue arose, how could I know that I would get due diligence and good faith support versus being used as a scape goat? I'm pretty anal about my documentation though, but it's the principle of the thing.
Seriously, there are people that just are lowdown jerks that smile and seem to get away with it...for a while. Usually it catches up with them eventually.
Education/academia, research, and healthcare can be much more cutthroat than people realize. It comes as an alarm, b/c these are all supposed to be altruistic areas--at least somewhat. 😉