@jale66 It’s possible the original blood test was wrong or something happened at the lab. Try not to panic but absolutely get in with your doctor.
If you begin to experience severe abdominal pain or begin having very heavy bleeding, consider going to an ER just to be safe.
@ammi Blue line tests are notorious for bad indents and evap lines. At this point you should have a very obvious positive. If you post a pic of the test though to r/lineporn you can get some feedback to confirm.