20 weeks with a short cervix!! HELP!!

At 20 weeks we were so excited to find out we're having a little boy!!💙 Then we were hit with the news that my body is very close to failing my happy healthy baby boy. My cervix was measured at 20 weeks measuring 1.7cm (normal measures 3-5cm I was told). I went back 5 days later and they measured 1.9cm(we were told depending on how they hold everything it can measure a tad different)so basically it stayed the same which is good. I've now been put on bed rest and progesterone intravaginally to try and keep baby in there as long as possible. Please who else has gone through this with a positive out come?? How long were you able to carry baby?? Any tips for things I can do while on bed rest to help my body??