Two rounds of letrozole in one cycle? Anyone with a similar story?

Kim
Hello ladies I started my first cycle of letrozole this month!!! The doctor gave me 2.5mg from CD 3-7 I then went on cycle day 12 to get an ultrasound done and only had a 9mm follie. The doctor Told me to double the dose from CD 12-16 when I went  back to the doctor I had one follie at 18mm. I am now in the tww... Does anyone have any success with this? 
Thanks baby dust to all!!