could be implantation bleeding wait a couple days and take a first responce early result test. Good Luck
anything is possible! brown discharge signifies old blood and mother nature could be throwing a curve-ball at you when you thought you had it all figured out. but the light bleeding and pain could also signify a tubal pregnancy which is very serious and if you don't get it checked out, it would be very bad for you. go to a local clinic if you don't have insurance. if the pain intensifies in any way or becomes more constant, get to the ER, insurance or not.
Good luck
The symptoms your describing are normal in the beginning stages of pregnancy but there's no way to say for sure if your pregnant or not just from what you've posted. The only way to be sure is to take a pregnancy test,I'd recommend an early response test or make an appointment with your GP. x