I took plan b 5 days ago within 48 hours of unprotected sex. partner did not ejaculate inside. today i had heavy, dark bleeding that filled a regular tampon in a very short time. now the bleeding has subsided. was it spotting or a plan b side effect?

Yes: Plan B, sometimes referred to as the “morning after pill,” is emergency contraception you take within 72 hours after unprotected sex. It contains a high level of hormones that interfere with the implantation of a fertilized embryo. It should not be used regularly as the levonorgestrel can have side effects including nausea, abdominal pain, fatigue, headache, irregular bleeding, breast pain.