HELP!! Non-implantation spotting ahead of AF - is it a problem?

Lisa • Married 5 years to a wonderful man. Son born 26 Jan 15. Expecting another boy in Nov 16 X
Hi there
​I keep spotting at 9 DPO for 3-4 days before AF shows around 11-12DPO
​Spotting is always very dark brown and is not heavy enough to need protection other than one very thin panty liner per day.
​During this spotting my temps remain high.
​Anyone had this issue and still got BFP? I'm just concerned it might be lowering my chances of conceiving.
​Any insights welcomed