Clomid failed, letrozole this cycle. :/

Jaimee
So last cycle I was given 100mg of clomid and I didn't have any mature follicles. After three ultrasounds and the emotional strain I just decided I wanted to cancel the cycle. 
My RE decided that clomid wasn't going to be successful for me and this cycle he's starting me at 7.5mg of letrozole cd3-7. 
We're going to have a follicle check probably around cd12. 
I'm currently on provera and have two more days after today. 
I would love to hear success stories with letrozole after clomid didn't work. 
We're you able to go through with iui? What were the results? :) 
I'm feeling pretty positive and optimistic about this cycle. But I also felt that way with clomid. :/