I got called in to see a high risk pregnancy dr....

Im currently freaking out and don't know what to do. My Drs office just called and scheduled me to see a perinatologist ... my 20 week scan was about 2 weeks ago and at that time from what they could tell things were going good, only area of concern was a low placenta but it wasn't covering the cervix. But now that I have to go see this specialist I'm freaking out. I have no clue what to expect. If there was something really wrong wouldn't I have been informed sooner?? Any words of wisdom here or other mommas dealing with the same thing please let me know ☹☹☹