When did you ovulate on Femara?

Kristin
I took 2.5 mg Femara CD3-7 (first round after lack of success with Clomid). I am on day 17 and still opk negative. I use the Clearblue Digital and I am not even getting the flashing smiley!  Last month I did ovulate on Clomid but not until day 22...is there still hope for me?  I thought I would ovulate sooner on Femara but I'm hoping there is still hope. Thanks!