I had a late period, 7 days of cramping, two days of very light/brown spotting, then a period. My doctor thought I had a miscarriage right after it implanted. But when I got a blood test three days later, it was a negative for hcg. Could I still have had a miscarriage without any hcg hormones in my blood? What else could the 7 days of cramping (and a thick feeling) be?