2002 Toyota Camry car unstable on highway

I recently took my car for an oil change and had the mechanic check my exhaust and shocks. Reason for this is that it sounded like there was a hole in there or something from the exhaust. Also it turned out to be more bumpy driving these days and when driving on the highway at higher speeds in strong wind and rain the car did not stay on the road. It kept swaying side to side, needing full control of the steering.