Can Having Unprotected Sex After Late Beginning Of Pills Cause Pregnancy?

I had sexual intercourse on March the 28,2011 that was unprotected, i started my birth control pack a week late and i did not have an period in march because i skipped my brown pills at the end of the pack. On the following wedsday i took next choice emergency contraceptive and im still taking my birtch control pills, i was also on amoxicillin for an ear infection. Is there an risk that i can be pregnant?