I was 17 wks when I got induced to have my son who had no heartbeat on our 16wk u/s.
I remember hearing and feeling a 'pop' noise and immediately had hubby get the nurse, she checked me and it was my water that broke.
Get to Dr. ASAP.
I didn't feel the 'woosh' of the waters breaking because it broke upwards, causing it to be pooled in my uterus.
That could be that your water has broken but if you don't feel water coming out then the baby's head is really lowered in your pelvic area that it's like a plug so it's not letting the water come out. Call your doctor.