Measuring behind at 15 weeks

So I went to doctor today because I’ve had cramps and spotting. Honestly I’ve had it this whole pregnancy but it was more blood than usual and cramps were more intense.

I saw my OB at 12 weeks and everything looked good. She had me on progesterone because my levels were low. Once she saw baby though she was happy and took me off medicine and pelvic rest.

Well today she said baby is measuring only 13 weeks and should be at 15 and also my amniotic fluid is low. Heartbeat was strong. She said she doesn’t have an answer for me as to what is going on and referred me to high risk specialist. She also ordered genetic testing. I of course googled and now am freaking out. Should I expect to lose my baby or has anyone had positives come from this? I’m seeing birth defects as a possible cause online. My appt isn’t till next week with high risk OB and genetic testing is 7-10 day turn around. so I’m sitting here scared and worried. Anyone have same kind of issues?