possible miscarriage?

Hi, I recently was considered about have a miscarriage I'm 13 weeks pregnant & I started to bleed some the other day but the next day it was brown I went to the doctor they took blood & told me my percentage for the baby went down is it possible I could've lost my baby because it take up to 2 weeks to have a full miscarriage & I haven't bled since the last time which only lasted 2 days.