I had my normal period at the usual time I always do. The day it ended me and my boyfriend had sex. We used protection, but it broke. So the next day(2nd day after period) I took Plan B (the morning after pill) just as the instructions said. Now a week after my period I'm having a normal period. What does this mean? Also after we had intercourse I noticed muggy red discharge and thought I was still on my period but it was just discharge.

It is pretty common to have bleeding after using Plan B due to the high levels of hormones for it to do the job for which it is intended. The light bleeding after intercourse was likely remnants from your period which had just ended a short time before. Chances are your cycle will get back on track next month.

Well the bleeding has got really heavy I went threw 20 tampons today

Bleeding after Plan B can sometimes be quite heavy. If it continues, or you are concerned that it is more than just a very heavy period type bleeding, give your doctor a call.