Ultrasound didn't know if my water broke. (29 weeks)

The ultrasound lady told me she didn't know if my water broke or not (I'm 29 weeks, 5 days). And my cervix is 2.3 cm... She said it was short.

How would they not know???? Basically I'm freaked out.

I waited all day for the Dr to call me as they said she would. Finally the Dr calls and tells me she has been trying to talk to the ultrasound people all day and they haven't talked. She said she will let me know tomorrow, but if I start having regular contractions to go in. I'm freaked out. He is only 3 lbs right now.

Has this happened to anyone else? What did they have you do?