Am I pregnant?

I think I may be pregnant but I don’t know, and I don’t wanna panic or freak myself out if it’s nothing, but I didn’t have my period so far this month, and I guess technically I didn’t have it In July either. Well my last period started on June 26th and ended on July 2nd, so technically it rolled into July, anyways, I went to be put on birth control on July 18th, I had sex that morning and had sex on July 4th and 5th (I’m very proactive about documenting it) anyways they obviously tested me and it came back negative, I got on the depo shot for birth control and went about my day, now here we are on august 8th and I should’ve gotten my period around July 30th but I didn’t. I don’t know if it’s from the shot, or from the amount of stress I’ve been under lately or if I could be pregnant. I don’t know how that math really works and if the test I took on the 18th was negative then if I was pregnant it would’ve had to have been from when I had sex on the 18th right? So could my period not show up just 2 weeks after? Could it happen that quick? I’m just so loss and scared.