Period forever??

Hey lady's I was supposed to have my period the 18th of June through the 23rd, well it was late by 3 days then on the 3rd days late I started getting brown discharge (I never have brown discharge before my period ever and it's never been late!)  well I have this brown discharge for about 4 days. Well I guess you would call it my period well it stated on the 26th and I've been on this period for 8 days! I'm a regular and never miss a cycle and I always have my period for 5 days then it's done.. Can anyone give me any insight on to what may be going on? Is this anything to worry about? Thanks!