Haiti trip down the drain?

So, for over a month now I've been trying to get the time off for this trip. It's in two weeks. The nurse manager of the ED and the nurse supervisor (the one who doesn't like me) have verbally said they don't see any problem letting me go. I've submitted multiple paper vacation requests, which all seem to disappear.

But I'm still on the schedule.

I've offered to switch days. I've actually found per diem and part time nurses who are willing to cover some of the days--the ones where staffing is really low. I've haunted the nurse manager (who I think has one foot out the door these days) and written emails and done everything I can think of.

And I'm still on the schedule.

I'm getting up early in the morning tomorrow to be there when the two of them come in, and will demand an answer--in writing. I'll be horribly embarrassed to tell the IMC, who is sending me to Haiti, that I can't go, but if the answer is no, so be it. I can't just not show up for work--I'll be marked absent, which is really bad. I have no paper trail that proves anything: I've submitted copies of vacation requests, but I don't have one that is signed, proving I can go.

What's insane is that no one else will be on vacation from my shift during that time period. I'm also the third-most senior person on my shift, so no one can beat me out anyway. I have over three months of vacation time saved up. What the fuck is going on?

I really feel like I'm getting screwed.