I had a late period and all the signs of pregnancy. I decided to take a test, but it came out negative. Two days later I started my "period." The first day was the worst pain I had ever experienced. Nothing would take it away. I clotted and had odd discharge. Cervical cancer and endometriosis run in my family. Am I experiencing early signs of that, or did I miscarry?

Not even 100 doctors online can answer this, of course.
You have failed to give us about 99% of the information we would need to even begin to guess, and asking you to answer each question would only be minimal help anyway.

You need regular GYN checkups because of your family history, so find one you like ASAP.