at my first trimester screen, the doctor told me i had low lying placenta. the nurse who did the ultrasound asked if i’d had any bleeding, to which i replied no as i haven’t. the doctor didn’t seem worried about it, but told me she wanted to have my OB watch it. i was 13w2d when i had the screen, i’m 15w4d now. should i worry? what are the chances of the placenta moving? am i at risk of it turning into placenta previa? i work in retail, so i’m on my feet 8-9 hours a day, lifting boxes/buckets that weigh between 15-30 pounds (i’ve not lifted anything over 25 since 6 weeks per my OB).