Hi I Had A Medical Abortion On July 18 I

Hi I had a medical abortion on July 18 I bled for only 3 days. I started taking my birth control pills right away. I had sex a week later, I took a pregnancy test today and it still shows positive. i am wondering if this is a new pregnancy or could it be that its still reading from the abortion. I am also having a few symptoms. Headaches and having to use the restroom more.