This is break through bleeding or spotting. Likely your hormones are out of whack. Any chance you are pregnant? If that is a possibility, take a test. If not, then see if it clears up and if it doesn't, see your doctor to get your hormone levels checked. Perhaps you are producing too much estrogen. Brown discharge is typically old blood mixed with your normal discharge so not really a scary thing other than you want to find out why you have it for a whole week. good luck