I had unprotected sex 2 days before my birth control was over could I be pregnant?

This is my first month taking birth control & my bf and I had sex on the 12th so I had 2 pills left till the last week when I start my.period. now I took the two pills but didn't take the last week when im supposed to start my.period cause my doctor said I don't need to take them there just to keep track of your.period. so it's 3 days & I haven't started my period.. is this normal? Or am I pregnant? I been feeling a little sick & I been having wierd pains in my stomach & lower back. Is this early sign of pregnancy?

You should go to the doctor!!!