Nervous about too positive of a test?

I'm over the moon right now as we are currently expecting our first little one. I am not sure how far along I am because my cycles were irregular. Last Monday, April 11, I took a cheapie internet test because I was not sure when I would be expecting AF. It looked negative to me so I didn't pay much attention to it. I started feeling sick and had very tender breasts so the next Monday, April 18, I took another and it came up quickly with a dark, strong positive. Later that night I took 3 more tests (so not even with FMU) and the test lines were darker than the control and the digital said "pregnant 3+". I was thrilled. But if I was already 3+ weeks since ovulation, shouldn't have the test the week before shown up positive too? Or does this sound like normal timing? Thanks so much!