Low anterior placenta - question

Hi, so during the 20wk us they told me I have a low anterior placenta (front side). It is 17mm from the cervix and it should be at least 20mm so I have to go back with 30wks to check if it moved up. Does anyone have the same? And Did you get restrictions? I bled a tiny bit when I was 18wks and told the technician this as well. But still they didnt give me any restrictions. Just wondering if you guys have same of different stories with a low lying placenta. Thanks!