Added brake fluid, now my brakes have no pressure?

i have an old 1999 ford escort which according to the cap on the main reservoir and manual, takes DOT 3 brake fluid. the brake light has been on for a few days now so i figured it just needed to be topped off, but when i did add some nothing was fixed. i pumped the brakes only after which my brake pedal lost pressure. anyone know what's wrong? thanks