cycle day 43, never started after provera

Erika
So I have been on clomid 50 & 100mg. For December and January. I've been taking provera for the last 8months but for some reason this month didn't work. I took provera from the 6th - 12th and never started. My cd21 progesterone lab was 0.4 last month. I have taken pregnancy test and all negative. So yesterday I went to the doctor, they did blood work, negative pregnancy test and normal thyroids. They told me some type of estrogen test was normal that shows if your body can ovulate? Anyone know what test this is?!? And also has this happened to anyone els? The doctor gave me more provera to start tomorrow for 10days and took me off clomid. So now I have clomid 150mg just Laying around at home(I was supposed to start it on my next cycle... The doctor will be starting me on Letrozole 2.5mg(generic for femara) anyone have success on this medication or can tell me some good info about this to cheer me up!?! Thank you