looking at the video, I don't think your stem's too long, by much, if any. You may just not be comfortable in a fairly aggressive position.
I'd ride the bike for awhile and see how it feels over time. and then consider whether you need to make adjustments.
And if you don't become comfortable with the position, the answer may be a stem with more rise, as opposed to a shorter stem.
Have you tried the test of whether the front axle is obscured in the drops?
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.