Period isn't normal after plan b, it keeps stopping and starting ?

It can happen: Irregular bleeding after taking a morning-after pill like Plan B, or Ella (ulipristal) is somewhat common. Some women get spotting or bleeding before the next period. Women may also have a heavier or lighter next period, or a period that is early or late (hard to predict) . A urine pregnancy test should be done 3 weeks after taking a morning-after pill, to be sure there is no pregnancy.

How long has this: been going on for? Potential side effects w emergency contraception include: menstrual flow changes (spotting, bleeding, early or late period), nausea, vomiting, dizziness, fatigue, headache, breast tenderness & abdominal pain or cramps. Take pregnancy test & notify dr if your period is 7 or > days late.