Hello ladies. I have a question regarding diagnosis if IC and maybe some kind words and reassurance

Last week I went for an ultrasound and then my gynecologist to determine cause of waters breaking at 15 weeks. The ultrasound came back normal, absolutely nothing wrong with my cervix. Then i went to the doctor hoping I’d get answers. But nothing specific. She told me she still suspects IC but i don’t get it how? If nothing is seen on US and pelvic exam. Then she gave me a plan of my next pregnancy. Weekly monitoring of cervix, which is not helpful at all because I had ultrasound the day before my waters broke and it was 3,9 cm. When i arrived at the hospital it was already 1 cm. So it shortened in just one day. She’ll be adding progesterone suppositories also. And cerclage from 13 weeks just in case.

I came out of my appointment pretty happy because i was afraid she wouldn’t agree on a cerclage. But then i got to think, what if it’s not IC and I will focus on it while there is another issue which caused pprom.

I would appreciate any insight on this. Ladies with IC, how did you get diagnosed? I know cerclage with additional supplements can do wonders. I just don’t know how my doctor diagnosed me with this if physically everything is normal. Is it okay?