Cervical cerclage 14 week 3 cm length.

I had cervical cerclage in 14 weeks and after 5 days of cerclage my cervix length is 3 cm but before cerclage it was 2.8cm my dr. Put preventive cerclage bcz I had 23 weeks of pregnancy earlier where my cervix got open n remain no length so this time dr put preventive cerclage...please tell me I can go full term with 3 cm I m also taking progesterone susten 400 everyday now I m in my 21 weeks I m very much scared I have to go for my anamoly scan next week so I m very much scared bcz previously my pregnancy was not succeeded I lost my baby girl at 23 weeks and in previous pregnancy my cervix length was 3.2 cm in 12 weeks but I lost all cervix length by 20 weeks which caught on anamoly scan n they put emergency cerclage but still I got water breaks in 22 weeks n 23 weeks I got delivered...this time I m very much scared bcz I m in my 21 weeks again n I have to go for anamoly scan does my cervix length decrease after cerclage ? Plz help