I am 6 weeks along and had brown discharge for about four days and now have white with a little pink. should i be worried?

No, but talk to PCP.: The short answer is no, you should not be worried. Many women can get spotting during pregnancy. This can be from an easily bleeding cervix. Bleeding can also be a sign of a problem but is usually more then this. Since this should not be a substitute for a physician visit I would recommend not being worried but follow up with your PCP.

Monitor situation: Monitor situation closely and make sure your obstetrician aware. I would not worry if us looks well