okay so here is my story i need advice on what to do and if im making the right choices :

i been on the depo shot for 3 years and i have been off now 6 months or so and i had a one day period on Aug 16th and that was all and then on September 3rd i had what some people told me was ovulation and had unprotected sex and then the next day i starting spotting for 4 days off and on and the next week afterwards i started having real bad headaches and nausea and still have them same symptoms. please help !!! (: