2 soft markers for DS

At my 20 week anatomy scan the baby was measuring perfect, but the doctor found that there was fluid in one of his kidneys. He didn’t seem worried about it and didn’t even say much about it. Next at my 33 week appointment the baby still had fluid on his kidneys and now his femur is measuring small. Of course I have done research on the Internet and it scared me. I was just wondering if anybody has had these markers come up for down syndrome and what your experience was!