Dilated cervix at 20 weeks

So I got my 20 week ultrasound today found out we are having a baby girl!!! Yay .....but my excitement was short lived We got a call from the dr about 2 hours after.  Because I lost my first baby at 21 weeks due to a placenta abruption they wanted to have picture of the length of my cervix just in case well the doctor called to tell me that I am dilated a little bit with membrane coming down(idk what that means) but I am now on bed rest for the weekend with progesterone meds and I go to the hospital Monday morning to possibly have a stitch put in has anyone had one put in this late and made it to term? My heart is breaking I can't lose another baby... As of now the dr said the goal is to make it to 24 weeks at least 😢