I Just Had A Medical Abortion A Little Over 3

I just had a medical abortion a little over 3 weeks ago. All my pregnancy symptoms subsided. I did have unprotected sex 2 weeks ago. and about 4 days after that my breast began to hurt again like I am pregnant so it concerned me that I may have conceived again. I did take a pregnancy test and it is positive. I really would like to know how can I tell if it is showing positive from the previous medical abortion or if I am indeed currently pregnant