I was 2 wks late then had a heavy 3 day period apposed to 6 light days... did 3 tests 2 neg 1 pos...... 2 wks later had 2 days spotting still neg test?

Pregnancy unlikely: Home pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, or medications. A correctly done urine test gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon.