I totally feel you! Even my DH sometimes feels like he wants a couple days off (and I try to make it so it isn't during my FW, but can't always help it!)...I even get the occasional question of, 'are we supposed to have sex tonight?' Sweet, honey, thanks...
But I definitely agree with the 'lube' comment, and maybe throw on a movie that gets you in the mood...can't hurt, right?