FTM help??

Julia • FTM. Blessed with baby boy ❤️
So I'm about 18 weeks and 3 days. So I've never like to wear a bra ever even before I got pregnant. I only wear them when I go out obviously but when I'm home I don't like to wear them at all. 
So this has happened to me about 3 times already I think, not on the same day but I feel my nipples wet. Not a lot but just like a dot and that's it. I find it strange? I'm not that far long, but I don't know?
When did you start leaking?