My period is officially one week late today. My period can go 2-3 days off the normal 28-day cycle, but this is excessive. My husband and I are trying to get pregnant, but I've taken 6 tests throughout the past week and all were negative. I recently traveled, and am moving next week so I'm stressed and my body clock is off. I feel like my period hasn't ever been thrown off by events like this before. How long is too long to watch for a positive pregnancy test?