first that does sound scary! sorry but glad all is okay. Do you think it may have been urine leaking out? I've heard that can happen the further along you get. Hopefully whatever it was doesnt happen again!
If I had had a big sneeze when it happened, then I would've thought it was urine (that has happened during the pregnancy). But this was when I was sitting very calmly and reading. It made a stain about five inches in diameter. And it smelled kind of like cheese :/. Sorry for TMI.
The dr said if it were my water breaking, it wouldnt just be one gush, it would continue to trickle out.
Anyway, I just wanted to share in case something similar happens to others.