Tonight is my last dose of Letrozole 3 x 2.5mg pills for 5 days (First Cycle)

I been having some cramps on and off, also been spotting since the 3rd night, it's just when I wiped and looks like Pink reddish color. I started Letrozole without a period.

Last night Husband and I had sex, This morning I have more spotting thn the last 2 days, I'm wondering if my period is coming or if this is some kind of side effects of the pills? I'm also taking 1,000mg of Metformin(I have PCOS/insulin resistance)

I'm going to see my Doctor on Friday for a Transvaginal Scan to see if Letrozole is working but I'm concerned that maybe is not😫

This happened to anyone? Is the spotting a side effect?