I'm 100% sure i'm pregnant. a month late passing menstrual date with light spotting. negative tests. bloods on the 31st. am i pregnant or crazy!?

Not pregnant: Today's home pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, vaginal spotting, or medications. A test gives a reliable result 3 weeks after sex (or when conception might have happened) or 1 week after missing a period. If done sooner, a negative result may be due to testing too early, such as less than 2 weeks after conception.