Is brown discharge normal?

Its my first pregnancy and i wasn't expecting it at all . I was late for a week and decided to take the test and its positive . The doctor schedule me to take ultrasound in 2 weeks time but i am so worried because i had brown discharge . Its not a lot but it is there every day .i am still working full time , is that mean i am just tired?  Is that normal? Im so worry 😳 . Im 5weeks now according to when i got my last period.