Letrozole and bleeding

I have PCOS and I’m doing induced ovulation. My first round went well, got pregnant, but sadly ended in a 9w miscarriage. Now, a few months later I’m on my second round. I took 5mg of Letrozole on days 2-6 of my cycle, i.e. while on ny period. My period stopped on CD6 with a bit more light (pink/brown) spotting on CD7. Today, CD8, we baby danced. It felt a bit dry so we used lubricant, and even added some more as we went. This was at 5:30am (gotta make it work around our busy life). Then at 6:00pm I went to the toilet and had pink/reddish blood. Not a flow but quite a bit when wiping. At 7:00pm checked again and there were a bigger wipe (not sure how to explain), but has since stopped to just a bit of pinkish.

So my question is:

Could this be from BD in the morning? Seems like a massive gap.

Is this normal and just caused by Letrozole?

I have my first scan on CD10 (in two days) and I’m worried the lining will be too thin…

Thanks