Hello there. Thanks for writing. Depo provera when used for contraception causes delay in fertility. So you might not conceive for the initial months after stopping the depo injection. It takes a median time of 10 months following the last injection to achieve pregnancy. So you should not worry and give time for hormonal imbalance to correct. Brown spotting and light periods are a side effect of depo provera use. This would also settle in few months. Tender and sore breasts can be due to provera use itself. For your satisfaction you can do a pregnancy test to be sure especially if your cycle was delayed. take care.