My OB asked if I was leaking fluid

At my appt. today my OB asked me if I was leaking fluid (first time she has asked) my initial response was no. But now that I'm home I've been wondering how I would know the difference between fluid and the increased feminine discharge. Any experienced mamas know the answer? 
I'm 25w but measuring 24w. I looked up causes for this and one result is to little amniotic fluid, which is why I'm wondering about leaking fluid instead of having increased discharge.