pregnant ?

Zo
Is it possible to have A positive test still from a d & c a week before xmas ? 
 I thought it was all out of my system as I havnt felt pregnant or Hormonal since the d & c everything went back to normal pretty fast and I have had 2 regular periods since on time and normal. 
I have got sore boobs back and bloating quite hormonal and tired. I took a pregnancy test on Friday which said pregnant and 2-3 weeks. But I never tested for a negative after the op so I'm worried. 
I'm not due on my period till Sunday the 5th  march and I thought you ovulate 14days after period so I'm confused how I can already be 2-3 weeks pregnant. I only finished my last period on the 11th February. 
Sorry it's a confusing post would be grateful to talk to someone if anyone understands.