...leaking amniotic fluid??

I have been noticing some yellow watery stuff the past couple of days when I wipe, it isn't when I pee or when I have to pee, it's just at random times. I called my doctors office and the nurses said unless it's happening all day it isn't a big deal. I just got out of the dentist office and noticed my leggings were wet and they are soaked. My leggings have a smell but not a strong smell, not like a urine smell. I urinated a few times before I went, and I had no idea this even happened I didn't really feel it coming out at all.. I'm not really sure what to do. I'm 18 weeks and concerned.