What Causes Delayed Periods And Brown Discharge?

im 11 days late. go brown discharge too. but on my 8th day ,there was a drop of blood and thinking it was already my period but nothing follows. i wore panty shields and there was no sign of blood no more. still getting little brown discharge every day.i took pregnany test 1 week after my period was delayed and its negative. feel sleepy all the time and sometimes tired too. am i pregnant or not? pls help