help with early miscarriage or chemical

fa

on Feb 14 I got my positive hpt. a few hours later I start bleeding really heavy with very small clots .here I am 11 days after first day of bleeding and I'm still bleeding its changed from spotting to light .something just don't feel right .I took 3 more test and the second was light and on day 7 I took last one and it was negative. How long can this bleeding last help me