In need of advice, please..

Hello ladies, 5 weeks ago I suffered a miscarriage it was the hardest thing I had ever gone through. My doctor was supposed to put me on birth control, the depo shot to be exact because I wasn’t ready to get pregnant again right away. Last week when I went to the bathroom I noticed that I had light pink discharge, and from then on I’ve been having symptoms ranging from aching boobs, to a upset tummy, mood swings.. etc. I took a test this morning and I thought it was negative at first until I looked closer and seen a faint positive. So my question is should I expect to be pregnant again? Or is it possible I still have hcg in my pee from my last pregnancy? I’m so confused on all of this how could I get pregnant again if she gave me the shot 😢