I am 18 and a virgin and for 3 1/2 months now I haven't had my 'normal' period just brown discharge for a couple of days this has happened maybe 3 times and usually around when my period is due. 4months ago I started my first job in fast food. I am not sure if I should be worried that there's something wrong or it something else

Not really worried, but it is time to go to your doctor for a check up on this and any other possible female issues.