I m recently started taking the depo shot as a method of birth control in Mid August. My obgyn did not check for a current pregnancy before giving me the shot. One or two days after the shot, I had the worst lower back pain and sharp stab like pain on both sides of lower abdomen. I went to the hospital and urine test came back negative for pregnancy so they sent me home telling me it could be side effects of the depo shot. My last period was in late July. And I ve been bleeding a light brownish blood since the shot but my concern is on Friday, while I was getting ready I had heavy bright blood coming down my leg. I wiped it and put on a pad. When I went to go check my pad a few hours later--there was no blood at all on the pad. Now today is Sunday and the same thing is happening where I m bleeding and I wiped it off and it just stopped. What could be happening? Is it possible I can be pregnant but my urine test are coming back negative?