Brown spotting?

Kristin.
I am 11dpo approx. and had dark brown spotting for a few hours (10dpo) yesterday. Nothing went on panty liner, just when I wiped. Cervix is lower..no cramping or anything.  BD day before +opk, next day I got +opk, didn't BD on that day but tested next day and got another +opk and BD that day. Any ideas? TTC #2 for 6 months.