Due date..

I know it’s IMPOSSIBLE to know when I conceived my baby. I have all the dates jotted down when we tried however the date it shows by going off of my LMP doesn’t make sense lol. Is it possible to get a faint positive after 2 weeks of conceiving? I got a faint positive the 19th and it’s showing that I conceived this baby the 3rd of September. We also tried the 28th of August and if you count up 3 weeks from the 28th, it’s the 18th... so part of me wants to believe it was the 28th. I won’t know until tomorrow 😂 but Is it possible to get a faint positive at 2 weeks after conceiving?