is there a sort of droning noise? i remember when one of my old golfs had a totally worn wheel bearing it made a hell of a noise and felt "wobbly" so that might be the answer.
Jack the car up and check each wheel for play, if theres any, the bearings gone.
The wheel bearing is starting to go on my current golf, unfortunately, i cant check it, because iv got a hole where my jacking point is! grrrrr