When to start letrozole?

Autumn

Hi everyone! My fiancé and I have been TTC for almost 2 years. I was diagnosed with PCOS a few months ago. I have taken letrozole 2.5 twice last year. I am now seeing a new OB who is amazing. I am on letrozole 5 after a round of progesterone to have a withdrawal bleed. Okay, here’s my question though. I have been spotting for 5-6 days. My full bleed cycle hasn’t started. I was supposed to start letrozole on day 3-4 of full bleed. The spotting hasn’t gotten heavier, so im worried this is my actual cycle. Should I go ahead and start the letrozole, or wait and see if a full bleed happens? Has anyone ever experienced anything like this? Currently waiting on a response from my OB, but I’m impatient lol.