Thanks for the query.
After termination of the pregnancy
spotting can be seen to one to two weeks.
As your last ultrasound
confirmed that there are no retained products or uterine infection
no need to worry.
The time taken for returning of the menstrual periods vary from person to person after termination of the pregnancy. Some women may get it immediately after one month of termination.
So the bloody discharge now you are having could be sign of beginning of menstrual flow or it could also be post-ovulatory bleeding. Better to use some form of contraception
for 2 to 3 months to prevent pregnancy.