I have been spotting for 6 days. period has not came. isn't due until next week. should i be concerned?

Depends: There are many causes for spotting. If this is a one time occurence I would not be too concerned, however watch your pattern over then next 3 months. If continues to occur then I would seek further evaluation. If the spotting is associated with any other symptoms such as fever, chills, abdominal pain, shortness of breath, nausea, vomitting...then seek care sooner