A very similar thing happened to me at 23 weeks in my first pregnancy. It was upon waking up in the morning and I totally gushed about 60 ml of fluid, enough to wet through all the layers on the bed. DH thought I accidentally did a wee but I knew where it came from. I called the hospital and they told me to put on a pad and wait a hour or two to come in since they were full. Nothing more came out that I could tell. They did a quick swab, went away for 10 minutes, and said it was just discharge. I kept asking them questions because I never knew you could have discharge that was just like water as it has always been more mucousy but they were right. I think if 6 hours passed without more then you're good to go. A tear in the amniotic sac would continue to leak.