Leaking after sex?? Is this my water?? 18 weeks

So tonight after inter course with my hubby I had a weird deep "itch feeling" that almost tickled from the inside. It went away and I felt fine. We were laying on the couch watching a movie when I realized I had a watery discharge coming from my vagina. I went to the bathroom and it was almost pure water, maybe a little mucus like and had no color or smell. I don't want to sound dumb but could this be amniotic fluid or is it just normal after sex discharge?? I'm really nervous