I took plan b about a month ago. i got my period a week early(heavy flow). now im getting my period and its a very light flow. i took 2 pregnancy (negative). i had cramps and all my usual symptoms, but its never been this light. side effect?

With this type of irregular bleeding, and the possibility of pregnancy outside the uterus (ectopic), obtain a serum HCG test, as this can detect very low levels of pregnancy hormone. See your GYN physician for a exam and other testing, and ask about low dose oral bcp's.

The alteration of hormonal balance by plan B can cause menstrual irregularity. You could watch and wait. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex : https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines

Please discuss this with your Gynecologist who has your complete medical history. If you are not confident with your Doctor please see another for a second opinion.