So I had my last period 2/1/17. Missed my expected period 2/27. Took two at home test came back positive. Went to the dr today cause I had some bleeding. Did an ultrasound couldn't see anything but was measuring to be about 4 weeks. Doctor said urine test came back negative. She said it could be to early to detect there at the office or I had a chemical pregnancy(miscarriage) what are your thoughts?