How many days did it take you to get a positive pregnancy test?

Well i didn't test until i was 8 days late, i wasn't trying so i was just kind of waiting it out. I took the test first thing in the morning because i read that is the best time to take test since the pee wont be diluted. I would wait if you can 3 days and re test if you still don't get your period. Levels double every 72 hours.