I’m worried 😦

Heather

So I am 17 weeks today , I went to the doctors last week he told me not to have sex or lift anything heavy and to take it easy because my placenta is still low . I went in today for ultrasound he said it’s still low just to take it easy that it should move up with my uterus as it moves up and grows it’s just taking a little longer this pregnancy (I have 2 girls ) never happened with them . Has this happened to anyone before.