Depo provera pregnancy

Okay so this is the first time I've ever had the shot but I had a pretty long period a month ago when I first got it and I was Starting to have cramps and all of the menstrual symptoms for about a week and I was supposed to start my period today but it's not here and it's always exactly on time but my boyfriend came in me twice a few days ago so I'm not sure if my period isn't here because of the shot or if I somehow got pregnant even with the birth control but I still have about two months until the shot will wear off so does anyone know what kind of affect that would have on a baby if I was pregnant? Could it kill the baby or cause birth defects?