I have been off the depro for six months I finally started to bleed but for only one day and it was very dark brown. I also took hpt and it was negative five times.
Could I be pregnant

Normally, I believe, they say it takes 12 to 18 months to become regular after the depro shot. I would say the bleeding for one day was a side effect from the depro shot, especially since 5 HPT tests were negative. Are you having any other signs of pregnancy? If not I would assume it is the depro. Contact your doctor and let him/her know what is going on and ask when your periods should be back to normal.