early miscarriage questions

I was four days late when I got my BFP. my blood hcg levels were at 51. when I met with the doctor a few days later she redid the hcg blood work since I was spotting and found that my levels were dropping. I started bleeding heavier than spotting as well. I had light, period like bleeding for three days but I am concerned at the amount of bleeding I had compared to what I was expecting. I had much heavier periods on occasion and was expecting a miscarriage to be heavier bleeding. Has this happened to anyone? Please help ease my mind so we can start ttc again....