Got a + test 12 days after lmp

I had wich I thought was my lmp on Feb 2-4 . 12 days later I started spotting brown  .. I also noticed that same week that I had my period some pregnancy symtoms so I decided to do a pregnancy test. When I did it quickly turned positive. I called my dr  and he told me to go get blood work. 
​I don't want to worry but I'm just scared that ima have an early miscarriage . Iv been spotting for 3 days now. Tomorrow I'll get the blood work results. 
​Did anyone experienced any thing like this ??