Clomid has failed yet again!

I have PCOS, I have super low progesterone levels causing me to not ovulate on my own. I have 3 children. My first, 8 years old, is product of coming off of birth control and jump starting a cycle. Just happened to catch it. After 6 years of trying on our own we were able to see a fertility speciaist. I did 6 rounds of Clomid. None of which worked. My first round of Letrozole was my second pregnancy, which resulted in a miscarriage at 6 weeks. Immediarltely following my miscarriage (DR approved) and 1 more round of Letrozole, my third child is 13 months. We want one more, really want to at least be pregnant prior to my 30th birthday (this October). I had to take Provera again to bring my period on again. I started January 23rd. I had gone to my Obgyn this time due to thinking I would have had to have a referral to go back to the specialist. We she had me do Clomid again. Said she wanted to do a couple rounds at least of Clomid before switching to Letrozole. Half way through this round I was informed the way they do their billing caused my insurance to not cover anything. So I contacted the specialist who I previously went through and my insurance covered all office related procedures. So I switched mid cycle back to my specialist. She questioned why the OB didn't just go to what we already know works for me. Honestly so did I when she wanted to do Clomid. Well today I had a follicle scan. I wasted my time with Clomid yet again. I have good lining, but my follicles are no where near what she wanted to see. So today I start the Letrozole again, with instructions of starting back up the prometrium once I ovulate to support pregnancy. I have had to take it for the first 12 weeks for all 3 of my pregnancies so far. I am frustrated however not surprised with Clomid failing me yet again. Sorry just needed to vent.