Just thought I'd add an update: I called my Doctor today just to see if he had an opinion. They asked me to come in to see him. He's the best doctor. He never makes me feel silly - even when I'm feeling silly myself. He said that since I'm 8DPO he wants me to have a blood test. If it comes back positive, we'll do another one in 2 days time to see if the HCG levels are rising and then go from there. If it comes back negative we will look at other options as to why I might have this brown CM during my cycle.

I'd still be interested in hearing from anyone else who has an opinion.