It could just be due to the abortion, i woukdn't worry too much. You should look into birth control methods so that you can prevent another possible pregnancy. Goodluck. i hope that your period returns soon.
Brown blood is old blood its possible it could be related to your abortion still ..I had a dnc after I miscarried which is basically the same procedure as an abortion an spotted for at least a couple months on an off ..are u on a birth control now ?? U need to be ..if you have started one recently this could also be the cause of the spotting ...