I took 2 plan bs within the same month and my period comes on the 18th but todays is the 15th and im getting brown discharge what could that mean?

Irregular bleeding: 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.