Warning, may be TMI!

I can't work out if it's just due to first trimester m/s but I find my mouth watering a lot, not to do with food or anything, just at odd times. It's not usually accompanied by a desire to puke but I have had the same feeling before when I wasn't pregnant, I would get a lot of saliva just before vomitting. Is it a pregnant thing? I can't remember having this last time. It really is pretty gross. Don't get me wrong, at other times I do feel very nauseous, but I don't have the watering mouth then. Weird, huh?!