I've had the same - sneezed and a tiny bit of wee. Really triggered me to start my pelvic floor exercises. Now make sure if I feel a sneeze coming on I tighten my pelvic floor first. Seems to be working so far, so fx it'll keep working as Lo gets bigger and presses more and more on bladder. I also read somewhere that if you don't always go to the loo as soon as you need it, and practice holding it for a little while that can help, as you're muscles don't get used to the fact that you are going to always go as soon as you feel the urge. Obviously don't keep holding it so long it's uncomfortable, but just enough so you're muscles have to do a little bit of work. Also, whenever you do go make sure it's all out IYKWIM.