I need advice

Found out the 8 of June that I was pregnant. On the 12th I started spotting which turned into full on bleeding. Went to the doctor on the 14th and they did a pregnancy test, said it was negative and that I had miscarried. They did an internal ultrasound and saw nothing ( I would have been 4 w 5d) the bleeding stopped on the 16th. Last night 6/21 and today 6/22 I got two positive pregnancy test. Different brands and they were read within the time frame. What is the world is going on? Am I still pregnant somehow? I heard it sometimes takes a little while for hcg to leave your body but the doctors office test was negative.  Help!