I don't think there is anything to worry about. From what my dr. told me, brown is fine. That is residual / old blood. I am 11w4d and I have had some pinching - not really cramps for the last couple weeks. Nothing I would even call pain, just pinching. Keep an eye out for color change but I think youre fine.
At your appt., did they do a pap smear? I just had my 12 week appt. yesterday and there was obvious bleeding when he was done with the pap. Now today I am cramping a little and the dr. told me to expect that and not to worry.