No Period after Birth Control

Advice. Me and my husband experienced miscarriage back in November 2017 I wanted some time to let my body heal so I was put on the Depo shot from January- April (only took one dose) it is now September and I still haven’t had a cycle. My dr put me on some medication to jump start it back in July and it still hasn’t worked? I have recently over the past two weeks experience back pain and nausea and tiredness. Could I be pregnant?