Headaches can be a sign of pregnancy...But it could have also been a migrane since it lasted 3 days straight. Have you missed a period? That would be a tell tale sign...If you havent missed your period you really shouldnt be analyzing signs just yet.

well the headache started the same day I kept having light blood spots... Like I looked up implantation bleeding and it sounded like just like, its not a period its just like "spotting" and the headache goes all the way down the back of my neck.

Have you taken a test?