Breakthrough bleeding or period?

I have been taking birth control pills for 10 months now. This last pack on pills I have taken, I missed the very last 2 pills before the placebo pills. I started bleeding and didn't bother taking the last 2 pills. I do not know if this is breakthrough bleeding or my period. Is there any way to find out? and what are the chances of me becoming pregnant? (the last time I had unprotected was before I missed the pills.)