What Causes Brown Vaginal Discharge?

sir i have two viruses positive in test.....n my doctor told me have no treatment for it.m so upset wt to do?is it serious problem.m 26 years old,5 nd 1 inch height,40 is weight,i had lost my 12 weeks pregnancy due to no fetel node,had D & C ONE week back,now having little brown discharge,sir it is dangerous ,shuld i go for ultradsound ,m worried