Low amniotic fluid?


How would you know if you have low amniotic fluid? I'm 25 weeks and had my last ultrasound at 19 weeks, without another one scheduled. I've had a lot of what I think is discharge, but it could be fluid and I would never know. I had my midwife appointment yesterday and had my first fundal measurement (measured at 24) and she didn't seem concerned. How would you even know?

I'm only a bit paranoid because our family (cousin) just experienced a still birth and it has us all a little shaken. I'm worried that we wouldn't know until it is too late since there are no ultrasounds to peek in.