I had fairly frequent spotting between 8 and 15wks, all is well and I am due to give birth in 5 days or so! As said above, dark or brown coloured spotting shouldnt really be cause for concern, as long as youre not cramping too. If you are Rh- you must go to get the anti D injection to prevent any problems arising though.
No we didn't just have sex. But we went to a festival all weekend so I would say I was pretty active at the time
Spotting while pregnant can be from many dozens of things. Have you recently have a cervical check, have you been sexually active, frequent activity, etc etc. The cervix is much more sensitive while pregnant and can bleed much easier than usual. Brown discharge is usually not cause for concern, as it's old blood. It's when it's bright red/pink and/or accompanied by cramping that it can signify a problem.