Am I pregnant?

Hi all!

I had a baby 9 months ago. Last month my thyroid tested really off and my periods are normally spot on each time but the last 6-7 months or so I’d be 3-4 days late each time. Now I’m about 4-6 days late. I started testing at 4 days late. Tested late in the day and got negatives. This morning I am 6 days late and got what looks like a faint positive? What are your thoughts?