Have you had a gush since?
I believe you can lay down for awhile, then stand up and feel another gush, it's your water.
You can also smell it. If it's urine, it should be semi-obvious.
When my water broke, there was a gush, but every time I shifted there'd be another one and my pants were wet to the knees by the time I got to the hospital and I still gushed every time I shifted in the wheelchair while waiting to be admitted. I left a puddle in the wheelchair. I also felt the "pop".
Either way, a call to the doctor might be in order. They can do a quick test to be 100% certain.