Took a plan b contraceptive a few weeks ago, experienced a heavy period after however i am receiving very faint positive pregnancy test?

Can retest in 1 week: Can retest in one week to be sure. A urine pregnancy test gives a reliable result if done correctly. One can test about 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. An Ob-Gyn doctor can evaluate any persistent or worrisome symptoms. Using Plan B can alter the menstrual period timing for that cycle and sometimes the next cycle.