Light period after letrozole cycle

I have pcos and was prescribed letrozole unmonitored at the lowest dose. I don’t get a period on my own, before taking the letrozole I took provera that AF was only 3 days. I believe I ovulated this past cycle because I had a bbt shirt and a +opk. My AF did start on its own! But it only last 2 days. With the first day being heavy and yesterday being very light. I took another easy@home PT this morning just in case because I am suppose to start round 2 tonight. Has anyone has similar experience?