look at the bright side here though please, I know a lot of female friends that have gotten pregnant and the guy skipped out on them-- they are having to be a single parent due to they can't track the guy down that is the dad.

The bright side is this guy you speak of, if I read it right, was willing to help out if there was a baby.

And ya know, if he does not want a relationship -- why bother if that is what you are looking for you have gotten your answer right?

The shot you mention, is it depo? (Depo-Provera)....
I am on that, and after a while no spotting, some time really horrible cramps though well before needing the shot (but it is different for each as well). Depending on how long you have been using it (if Depo) spotting even when missing a shot can be "normal".
I have also heard from reading from other women on other sites that use Depo that even after they stop getting it, some of them take a year with trying before they get pregnant with a baby,.

Sorry this may be sweet little nothings,

but hoping you well