pregnancy right after miscarriage

okay so. i took 6 tests in the last 2 1/2 weeks. the first week we started taking them, i got very faint positives. second week they were only showing evap lines after 15 min. this one i just took showed a line even before it was done developing. i had a mc on march 12th. & had a little bleeding last week, but nothing to even fill up a tampon. what does this mean? do you think it's left over hcg?