No period after one depo!!

Hey! So I'm kinda concerned... I had a baby in June and had the depo once in August and I didn't stop bleeding for the whole 3 months it lasted so decided not to get it again... I had one period around December and then.... nothing! I keep getting so paranoid that I'm pregnant but we are using condoms... took a test ages ago and it was negative... we still can't see doctors here unless it's an emergency... has anyone else experienced no periods after just one depo shot?!