My last period was n august 22nd and for the past couple of days i have been having brown spotting. my period is due on sept. 19th, i took a hpt on the 11th but it was neg and so was a blood test. what could be going on or could i really be pregnant?

Wait a little longer: This could simply be a little premenstrual bleeding, but it is really too early to be certain that you are not pregnant. Taking the pregnancy tests so early is not very helpful because the pregnancy hormones don't start to become detectable until about 8 days post conception, and the miscarriage rate then is very high.

Spotting: Sounds like low Progesterone spotting before your period. Keep a menstrual diary and see if it gets normal next cycle. If it persists, you may need a Progesterone boost. Other things cause spotting like polyps, fibroids and infections. And always consider pregnancy if it's a possibility.