Possible chemical?

So my cycle was longer than usual this time. I started my AF today after 39 days. I usually fall between 28-34 days.

I’m experiencing brown blood, which I’m aware is just old blood. I’m cramping a lot and there seems to be a lot more CM mixed in with the blood.

Is it possible this is a chemical?

I had a super faint line a few days ago and was waiting to test again on the day AF was due. I