What's going on with me??

Melissa
My period ended on January 4th. Today I woke up and I had a heavy amount of blood and very dark red. It's about 7:30 pm and last I checked its about gone. I had cramping after I found it and hip, pelvic and lower back pain with it. What could it be? I don't know if I should be excited (implantation bleeding), worried (miscarriage) or just random spotting.