I m 26 yrs old and I stated using the depo 3 weeks ago and last night I had intercourse with my bf and while we were having sex. The bleeding was excessive stain all over the mattress. I wasn t in any pain. This morning when I shower I notice some light bleeding. When I jump to the shower as I was washing myself I notice a very very small piece of meat but not a blood clot. 2 hours later I stated getting cramps and had lower back pain . After the shower I didn t bleed anymore and my back still hurts. What can it be?