It does sound as if you tested too early - most tests can't detect a pregnancy until at least 11 days past ovulation - and according to what you wrote, that would be September 1st. You could either retest then or wait until your period is late.

Remember that even if you get a positive then, it will probably be faint and that it would need to be followed up by your doctor.

Your history (2 kids) does make it unlikely that you have any sort of issues, so just take it easy & enjoy 'trying' if it doesn't work out this month.

Good luck!
Rachel Inbar
www.FertilityStories.com