O/D light flashing? check engine light?

A few weeks ago my car failed at the inspection station because the check engine light came on. They guy gave me a code, i looked it up online. It said I needed to get my catalyst converter fixed/replaced. I have yet to get it fixed and then tonight my engine light went off once i started my car and then the O/D (overdrive light) came on and began flashing. everytime i accelerated the car seemed very sluggish and did not accelerate fast. i have a 2000 mazda protege, can anyone help me figure out what this o/d flashing light means.