Light bleeding for the past 2 months, swabs came back neg for any infections or stds.not pregnant. (bleeding only at night)brown discharge in the day.

See details: When you say negative pregnancy test I'm going to assume that you had more than one urine test or had a blood test. Since that is negative and the STD testing is negative, you're most likely having dysfunctional cycles meaning you're not ovulating. I would however repeat the STD testing to confirm that they are negative. No test is perfect. Pap test and ultrasound also.