A couple questions...😩😬

Mi
So my boyfriend and I have been dating 9 months tomorrow and we have been really trying for a baby. But nothing has happened. We have been trying for the past 3 months. We have tried while I'm not on my period, while I am on my period and right after I get off of it during the supposed fertile time. But I have had the depo shot I was on it for several months and I stopped taking it after my ex left me. Does the depo stay in your system for a couple years or a couple months. We are really trying and we want to start our family. So if anyone has the same experience or has some knowledge about the subject please feel free to comments so I can learn what's going on with my body because every negitive pregnancy test really hurts both of us. Here's a couple 
picture of boyfriend and I 😍😍