I have the same type of discharge sometimes (I'm 12 weeks). I have many different kinds though, depends on when I check! However, when my discharge is how you're describing it, it's not a brown color. I would assume that brown is old blood, so I wouldn't worry about it too much. I think I might have an infection as well, but not because of the stringy discharge. It's the other kind that I get that's making me worry. I wasn't due to have an appointment with my OB until Aug. 5, but they bumped me up to Monday (the 28th), to check me out.
If you think it might be infected though, I would definitely call your ob just to make sure. At the very least, they can tell you over the phone if it sounds normal or not. Good luck!