I've had this on and off for months, it's just horrible. It seems to be in a good patch at the moment very little blood even when I brush, but at one point they would just randomly start bleeding-not when eating or anything, it must have just been my tongue that set it off. And my mouth would have loads of blood in it (think horror movie bloodstained teeth, lovely), with nowhere for it to go except swallowing, which freaks me out.
Weirdly, I think it has been my most pronounced non belly/boob pregnancy symptom...interesting!
So yeah, I sympathize!