Took plan b twice in one week?

You are not supposed to take more than 1 dose of Plan B in any one cycle. It is a huge dose of hormone for your body.

Plan B can delay both ovulation & your next period. As the first dose will have likely already affected things, the second dose will knock your cycle right out of shape, so it is difficult to know when you will next ovulate or have a period. You could experience heavy bleeding, even before your actual period comes along. You can basically expect to have hormonal symptoms over the next few weeks, until things settle back down.

The average fertile period is a few days around ovulation. The average ovulation is 14 days before your next period starts. I say average because no woman ovulates the same time every month. If you find you're taking plan B frequently you should get on regular birth control, its more effective and not as hard on your body. You will find you're going to have strange bleeding this month with a late period.