Well, plan B is a high dose of hormones that can seriously mess with your wife's cycle.

Side effects are pretty normal with Plan b. Some of the common side-effects are: headaches, cramping, nausea, fatigue, and breast tenderness. She will probably experience some irrgular bleeding or spotting for up to three months too. It's really hard to say what side effects she'll get since it's different for everyone.

Her period may be early or late, and it could also be heavy or light. There is also a possibility that your wife is very lucky and her period stays the same. Either way, as long as there's a period then you're usually in the clear.

If her period is late, then take a hpt to be safe.

well the thing is that the day we had sex (the day before she took the pill) it was the last day of her period so we know it cant be her period

No, the bleeding is breakthrough bleeding caused by the hormones. I didn't think it was her period.

Again, irregular bleeding (anything other than normal bleeding like her period) is expected. So she will/is having bleeding between her periods. And since she's already having side effects, I can tell you that her periods are going to be a little unpredictable for a few months (about the amount of time it takes for all the hormones to leave her system).

Don't worry, this sounds pretty normal. If the bleeding is heavy and doesn't slow after a few days, then you may want to speak with a doctor.