Thanks for writing in.
is a possibility unless ruled out. You should repeat a pregnancy test & also go for a trans-vaginal ultrasound
scan. With the given history ectopic pregnancy must be ruled out. If the pregnancy test is still negative & your scan comes out normal then you can consider your symptoms to be a side effect of depo shot. If the pain becomes sever then please see a doctor as soon as possible.
Please be punctual with your birth control if you are not ready for a pregnancy.
Wish you good health.