After a pelvic ultrasound 2 days ago doc found a cyst and today have spotting and cramps. my period is 6 days early? miscarriage, implantation, or ???

Impossible to say: It's is impossible to tell you the reason for your cramping and bleeding based on the informative you have provided. However, if you are 6 days early for your period it is unlikely to be a miscarriage. Implantation bleeding is also not as likely but not impossible. It could be a sign of an infection, your cycle could just be a little early due to stress or other factors and many other causes