Discouraged. How many follicles after femara or clomid? Menopur?

SF • We have a 5 yo and it took about 4 years of trying for our 2nd, due in July.
I just finished my first round of clomid and had my day 13 u/s today. There's only one 17mm follicle. There were two others that were small. None in the left ovary. I was on letrozole for 6 cycles, and had a lot of 11mm follicles, with one near 18-19mm on 2 cycles (I didn't do monitoring for all of the cycles). I'm feeling discouraged. 
I have menopur and will probably add that to clomid or letrozole next month if this one doesn't take. 
Fwiw- I'm 40 & my amh is 0.86
😔