My period is late, but 2 neg tests...

My period is probably at least a week late. Maybe more. I've only been off the pill for two months, so I wasn't expecting anything to happen, and my last period was weirdly long. At first I didn't think twice about it being late, I assumed my body was getting back into its natural cycle, but now I'm starting to wonder. Has anyone had multiple negative tests at first, but then end up actually pregnant?