Could i still be pregnant after a heavy period on time, plan b and neagtive hpt one day before period. when to take another hpt?

Pregnancy testing: The best time to rule out a pregnancy is if you are late by over a week. Plan B is a very efficient treatment to avoid conception after unprotected sex at a crucial time in your cycle. It looks as though you have been very diligent and effective in preventing conception, and as long as your period is on time, you should not have any worries about pregnancy.