2002 Renault engine shudders

Engine problem
2002 Renault Engine Size unknown Two Wheel Drive Manual 56,000 miles

Driving my car tonight I noticed it shuddering terribly! Upon opening the bonnet I could see the engine 'wobbling' so badly it was making the whole car 'wobble'. The engiine warning light eventually came on and the car seem to lose alot of its power! We have driven from london to birmingham in the past 24 hrs and the weather was lousy with a lot of spray, could this be something to do with it.
Please help!