Im 20 days delayed, i take pregnancy test last saturday but the result is negative.. but i notice some symptoms of being a pregnant.

Be patient: After 20 day delay and "-" test pregnancy is unlikely though not impossible. Skipping a period due to anovulatory cycle is quite common issue. Get some patience and wait till double time of your period (up to 60 days for regular 4 week cycle). If still no period and pregnancy test is negative - go to your doctor.Only comprehensive exam, pelvic sonogram and blood tests may establish your cause.