Six weeks after my abortion, and i've been having headaches,nausea,cramping,backaches,and vomiting. i have taken several pregnancy test all negative?

This isn't normal : It is important that you go see a physician to better determine what is causing your symptoms There are times after an abortion that all remnants are not removed or you may have an additional type of pregnancy going on. These symptoms are not normal after pregnancy and should be reviewed by a physician and have further workup.