How could this be?

Three positive pregnancy tests almost a month ago. Couldn’t get into the doctor until yesterday. (They wouldn’t see it until I was so many weeks along) I got a blood test done and it was negative.

I started spotting four days ago. The day before yesterday I bled a little heavy and had cramping. But it wasn’t that bad where I was scared. Told them about it and they didn’t seem concerned.

My question. Did I miscarry? Or was I never pregnant? Just missed a period? I am confused and heart broken. I go back to the doctors Friday.