What Causes Brown Discharge After Few Days Of Intercourse?

im 6 1/2 and i me n my boyfriend have recently decided to be sexually active we've had sex a few times with protect & its been about a week or a little more since. i recently started having a light brown discharge & some brownish spotting when i pee in wipe? i'm not sure if its just an infection or if it's more serious than that? it's only occured for 3days. please help me!