I had sex two days after my period we always use a condom and that night it broke. The next day evening I took the plan b pill. The next week I had cramps ever once awhile and they were little cramps. Then Saturday the same day the condom broke last week I got light bleeding? And little cramps. Is it because of the pill? Or what could it be?

I will assume you did not talk to the doctor, about the pill or even the druggist. Nor did you read the information paper that comes with the pill. The "B" pill has many many side effects, and one of them is to cause a period, or even sometimes to cause no period.

It is possible that you are pregnant, but most likely it is just the effects of the pill.

Also please be aware, that condoms alone have a 3 to 18 percent failure rate and many times those failures can not be seen, like a broken condom.
So merely using condoms can allow pregnancy.

You need to consider using a second type of birth control, to help in protection.

Also note the plan "B" is not 100 percent effective and gets less and less effective the longer you wait to use it. After six