Pregnancy? PLEASE HELP

I have been taking birth control for 3 weeks.  And I started bleeding and i had cramps on sunday     I bled all week.      Im still bleeding a little bit.   I start the placibo pills today. And i have had sex with my boyfriend but we used a condom. And none of the condoms were broken. We also did anal.  Without a condom
Soo is this my period or what?
And is this a sign im not pregnant?
I definitely do not want to be pregnant.  
 Please comment and help me.   I dnt know whats going on with my body