My last period ended on June 18. I have a regular menstrual cycle, and I was expected to have my next period on July 12.

I had my depo shot last July 9, and before the shot, I was tested negative for pregnancy.

I have read that the depo shot should be given on the first 5 days of the menstrual period, and if not given within those days, I should wait 7 days for it to be effective. Does this mean, I can have unprotected sex on July 16, and not get pregnant? My period did not arrive on July 12 or any days after.

Thank you.