Missed Period, what's next?

I'm 22 yrs old. So I stopped taking the Depo birth control two months ago because while I was on the depo I didn't crave or even wanted sex at all for the time I was on the depo nearly a year. I missed my period last month and I'm due this month for my next period but nothing yet. I've taken pregnancy test twice a week apart and it was negative. Not sure what to do next.