Could I be pregnant??

March 12 I gave birth to my beautiful baby girl. Bleed 2 weeks. April 24 I got BC shot. I had a lil spotting right before I got the shot when I had to pee first. May 1 I got my period it lasted a week. June 1 got my period it lasted 2 weeks. The first week light bleeding almost nothing and the second week heavier. July 6 got my period lasted a week. The end of July I had brown discharge with spotting lasted one day , then My fiancé n I went on vacation n had sex of course . 27-30. Now it's aug 10 my period not here . On the 6 took a pregnancy test cuz I was light headed most of the day and my period didn't show . It was negative . Yesterday I tested again and it was negative.

People are telling me it could've been implantation bleeding and that it may not show on a pregnancy test till weeks later. My fiancé moved to another state temporarily on the 31st cuz he got promoted and I haven't told him I could be pregnant. And I need to know now cuz if I test 3 weeks from now n say I'm pregnant idk if he'll believe it's his n maybe call it off idk. Someone help.