Pregnancy scare-on depo

Been on depo since May 2014 
Stopped having periods all together in September. 
Just recently I have a bright vein on breast and my stomach looks a little bigger. 
Is it possible im pregnant being that im on Depo, never missed a shot, and he NEVER has came inside me? 
I'm very nervous 
What do you think my chances are? 
Please no rude comments