I've been on metronidazole for a week until yesterday at noon. i also take tri estarylla, i took both meds. i had unprotected sex will i get pregnant?

Probably not: The only antibiotic that has ever been proven to decrease birth-control effectiveness is Rifampin--a drug used to treat tuberculosis. There are theoretic concerns about other antibiotics and you will see these concerns in print all over the internet but In practice, most common antibiotics such as Metronidazole don't affect birth-control effectiveness. Most likely you will not get pregnant!