Letrozole or Clomid?!?

Hi!! So I went to my OBGYN earlier this year and got blood work done that showed I was not ovulating. It came back a 0.2 on day 21 progesterone levels. I had no luck on round 1 2.5 letrozole but gave it another try, I finished round 2 of the 2.5 letrozole this month. My OBGYN actually moved so I switched to another one who said they don’t use letrozole they use Clomid. They still did my day 21 progesterone and this time it came back at 20.2 which means I ovulated on letrozole! I’m pretty sure I am not pregnant and on my next cycle the new doctor wants me to use Clomid instead of letrozole. Is this the right thing to do?? I need opinions!! Obviously it works because I ovulated but I’m still not pregnant so should I switch medicine? I’m definitely lost on what is best!