I had brown discharge 2 weeks after my last period, and now (lasted 2 days), and now 3 days before my next, i noticed light red blood...what could be?

Could be infection: This could be due to a vaginal infection or it could be normal after a menstrual cycle where you did not completely shed the lining of your uterus. In which case it could represent old blood. Your physician should be able to do a simple exam and obtain a culture in their office to evaluate for possible infection.

More details needed: Significance of such unusual vaginal bleeding depends on age, examination findings and other variables. Consulting your doctor with answers to these additional questions is appropriate.