Chemical or false positives?

Tw: miscarriage

Monday night i got a positive first response, and a positive clear blue digital. I was already nervous because i felt the line should have been much darker with how late I was. The next day I started bleeding. I took another that afternoon, but it was much fainter. That night my stomach was in so much pain and i was so nauseous we went to the ER. Their pregnancy tests came back negative.The doctor told me i wasn’t pregnant at all and it was probably false positives, and that my nausea was a bug that was going around (which i did end up having a fever the next day)..is it likely to have three false positives from three different boxes? Or was it a chemical?