I have a question. I was on a birth control pill from jul/23/2021

I have a question. I was on a birth control pill from jul/23/2021 until the week of 9/20(I stopped the pill cold turkey that week). I bled lightly the entire time I was on birth control which was my reasons for stopping it. The week of 9/20 I bled very heavy for about a week and a half(probably my body adjusting to coming off the pill). the bleeding ended up stopping. My husband and I had intercourse on 10/2 and 10/6. The week of 10/18 I got a faint positive pregnancy test. I had an ultrasound done on 11/6 in which I was 7 weeks and 2 days with an estimated due date of 6/23/2022. I am just curious as to which date I might have got pregnant either 10/2 or 10/6.