T.J.
The only way to tell is to get a blood test from your doctor. If your levels are still high, I would ask for a vaginal ultrasound to see if they can find the baby. Let them know that you are on the depo shot so they understand your concerns.
I've had 3 miscarriages and this is what they have done for me in the past for all three.
I would get this done right away so you are not worrying about it.
Good luck and God bless!