I'm 4 days late for my period. i took a pregnancy test yesterday morning and it was negative. i had a miscarriage in january but have since had two periods. could the pregnancy test have given me a false negative?

Unlikely: Home urine pregnancy tests are very accurate by 3 weeks after sex (a positive test result is accurate by 1.5 weeks after sex, but a negative result may be a false negative if tested too soon after sex), or by 1 week after missing a regular period. So, a woman with a negative result at 4 days after missing a period is unlikely to be pregnant, but if still worried, she can test again 1 week later.