A Depo Shot Question

Ariane • Daughter of my Heavenly Father, Wife of a Brave Airman, Boriqua <3
I started the Depo shot at the beginning of May. I've had spotting here and there. I've had my period once since being on the shot which was about 1 month and a half ago. I'm concerned that my period hasn't come yet again. Could I be pregnant or is it just the Depo shot messing with my period?