Pregnancy or not?

So I decided to take a test Sunday and it came out positive! Then Tuesday I spotted a little (picture below) and today I went to the doctor but they couldn’t see anything on the ultrasound but the doctor took my blood. I took another test at home because I was curious and it came back positive Has this happen to anyone else before this would be my first time getting pregnant. The doctor said it could be really early , or an ectopic pregnancy or already had a miscarriage.