Hello, i remember taking plan be back in August, after that my period is september was 2 weeks late negative test, november was 3 weeks late negative test again, and so far every month after that I've only been discharging old blood for 3-4 days as a period once a month, can plan b cause this? That's already 8 months total I've been like this, is that normal? I'm thinking about going to my doctor, any kind of advice or answer would greatly help!