17...Ne4 was a terrible, short-sighted move by black. s/he probably thought it clever because it would put pressure on white's queen when 18...dxe4, but he obviously didn't consider how the queen would react to that.
what a common mistake--just because you can figure out a way to attack the queen doesn't mean you should.
good job with the 16. e5 push (and following).
Another fun game.