Could well be from the depo. I would see your doctor for sure and have the tests I mentioned above done.
it has been this way for about 10 days now. it has lightened up but is still happening. i am kinda getting scared
Has it been brownish since it started, or was it like a normal period at first, but is now brownish? Are you on birth control? Birth control can cause this to happen.
A brown discharge is old blood, so it's not fresh bleeding. Brown discharge can occur at the start or end of a period, and it's just your body's way of flushing out what was left in there from your period. Sometimes, this can be the sign of STDs or bacterial infection as well. So if, in a week or so it's not cleared up I would see your doctor for a smear test and pelvic exam.