Been off depo-provera for 1 1/2 years still no period. and im only 18? i got on it when i was 16. plz help im kinda scared

Not uncommon: no reason to be scared. If having unprotected sex be sure to do home pregnancy test on first morning urine to be sure not pregnant. Repeat in 7-10 days. If both neg then very unlikely you are pregnant. See your Gyn provider. Some testing needs to be done. If all ok will likely prescribe you birth control for a few months to "restart" your menstrual cycles. This pretty common when women stop depo.