Depo shot.

I received the depo shot on 10/06 and I was supposed to start my cycle on 10/24. The last time I was intimate was 10/05 but it was withdrawal. I took a pregnancy test on 10/23 and it said negative. I'm aware that the depo shot does stop your cycle but does it really stop your cycle this soon? And do a blood pregnancy test come back the same day? I'm ???? to the doctor tomorrow.