I have been experiencing bleeding for about a week and a half, and I am wondering if anyone has any insight?

It started Monday(Day 1) and at first I was not  sure if it was spotting or a super light period, but I think it was spotting. That lasted until Saturday(Day 6), and then I got my period but it is different than normal. It is very light, usually mine rare medium-heavy and last about five days. Now it is Friday(Day 12) and I am still bleeding. I got Depo two months(early February) ago and I skipped my first period after that. I have been sexually active regularly since mid-February (we also use condoms), and I did have a very stressful situation occur the week before the bleeding started. 

Could this bleeding be the cause of Depo, or stress, or cause of something else? Please let me know with any thoughts!