Faint first response pregnancy Test after 8 days after heavy period.

Hello,

I got my period on 11/15 and ended on 11/20. I had a lot of cramping, heavy flow and clots for the first two days. It got lighter after the 2nd day but still cramping. However, my husband and I been trying to conceive and i don’t know why I decided to take a pregnancy test 8 days after my period ended which came up with the lightest faint line. The timeframe was within 3-5 mins and it was visible. However, is it possible to be pregnant even with the heavy period I had this month? Btw, I did had intercourse maybe (3) times prior to my period coming and about (3) times after my period ended. Any advice?