Negative blood test 4 positive urine tests

hey, sometime last week I took 4 pregnancy test at home and they all came out positive. As anyone would be me and my boyfriend were very excited, however during this past weekend I started to get a very intense pain in my lower stomach (which I thought was a bit normal) I had all types of pregnancy symptoms, sore breast, nausea etc. Yesterday at work the pain got worse as I I went to the restroom and went to wipe I realized there was some heavy bleeding. I decided to leave work and go to the urgent care as soon as possible by the time I got there I realized the bleeding was more of a menstrual period. They took blood tests, the nurse was very rude as to why I took four tests and not just one. After she came back with my results all she said was “You’re not pregnant” and let me go. Does anyone have any idea as to why I could have gotten those positives. The tests were not old tests and this would be my first pregnancy.