It could be a false positive test.
But before you assume this you should confirm that your last abortion
was complete. If after taking the abortion pill you did not get a check ultrasound
done to confirm the abortion is complete and no products have been left behind, then I suggest you should go for one now.
Birth control pills do not cause a false positive test.
test turns negative within 10 days after abortion if pregnancy is 6 weeks or less.
However at time with a pregnancy more than 6 weeks, the test remains positive for a month.
In both cases, I suggest you to go for an ultrasound to confirm if your last abortion was complete.