I would go to doc/er. In November of last year I had spotting for about 2 weeks. I didn't really go in because I didn't have any pain or cramps and was told some spotting is normal in the beginning. But I finally went in because I got tired of spotting and was diagnosed with a threatened miscarriage and 2 days later I had the actual miscarriage.
Any time you have bleeding in pregnancy, it's advisable to see your doctor just to make sure all is okay. COuld be nothing - bleeding in early pregnancy can be normal but best to be checked just in case.
If you get period like cramps or it turns bright red than go in. Otherwise its most likely implatation bleeding. I had it at the beginning of the pregnancy too.