Took clomid and none of the follicles matured

I DID CLOMID DAYS 3-7 AND GONAL-F DAYS 7-10 THIS TIME AND WHEN I WENT IN FOR U/S HE SAID THAT I DIDNT HAVE ANY MATURE FOLICLES AND THERE WAS NOTHING THAT COULD BE DONE THIS MONTH.HE SAID NEXT MONTH HE WANTS ME TO DO FEMARA DAYS 3-7.....WHY DID I NOT HAVE ANY THIS TIME AND WILL FEMARA MAKE A DIFFERENCE????