Positive tests and then a negative test

I was supposed to start my period on the 11th. I took 2 tests on the 13th. Each a different brand. And they were both positive. On the 18th I started bleeding heavily and having stomach cramps. I went to the hospital and they said the test they did was negative. They said they think I just had false positive tests. Everywhere I read has said that’s extremely rare, especially for 2 different tests. I did another home pregnancy as well and it was negative this time. Is it possible that I had an early miscarriage and already started my period again and my hormones already went back down?