Check engine light on

While on my mail route I hit some little bumps on a dirt road. Going about twenty mph. Got past the bumps check engine came on and motor sounded rough and lost power (lost lots speed going up hills). Got checked at O'Reilly's three misfires in cylinder one, two o2 sensor codes. Got o2 sensor fixed and changed the plugs and wires still have the check engine light on (light flashes when driving), and still seems to be the same condition as before. I do not know what else to do.