Brown/blood CM

Jamie-Lee
Just been to the doctors and tested negative. Im 12dpo, had really bad cramps Monday just gone and AF not due until next Saturday. My average cycle is 35 days. However, yesterday I checked my CM and it was a CMwhite, then I checked it this evening and it had blood in it but not fresh blood. I haven't got a clue what it means!! I'm never usually early on my AF!