Took Plan B had a period now I am spotting

I had unprotected sex on August 14th, within 12-24 hours I took plan B just in case, I am on Yaz and I don't miss any doses.  I know that I was in my third row of pills because on that Tuesday I started my white pills and on Thursday I started bleeding pretty heavy.  It was pretty heavy for 4 days but when I started my new pack of pills it stopped, I am in my third row of pills now and I have started spotting, someone told me that I still could be pregnant.  But I also have a yeast infection and I have been treating it with over the counter drugs, Generic Monistat cream. I told my doctor what had happened that I took plan B and then had my period she said that I was okay.  I have sore breasts but my nipples are not sore its like around the edges of my breasts, I have been pregnant before and I really don't have the same symptoms that I had then.  I have had breakthrough bleeding on other brands of BC Tri Sprintec and Junel.  I have not had sex since the 14th of August.  

[Elaine Brown, MD]

Hi!
I really doubt that you are pregnant, given that you are using a regular method as well as Plan B.  It is very common for Plan B to cause irregular bleeding, so I'll bet that is all there is to it.  I ALWAYS recommend taking a pregnancy test though, so don't skip that!
If you are consistent with your Yaz, you really shouldn't need the back up.  However, if you just want that extra bit of security, remember that Plan B is a hormone, and it will very likely cause side effects such as breast tenderness and spotting.  
Good luck!
Dr B