clutch problem?

i have a peugeot boxer 02/03 td van and just recently i felt a dink noise under the pedals then as driving noticed the clutch felt soft as if lack of pressure. and now its as if im riding the clutch when not even got foot on pedal. took it to mechanic who could not visibly see anything wrong, he lubed all parts but the problem still persists any ideas??????? also wondering will it cause further damage if i carry on driving and estimated cost for repair if anybody had same prob

marc/ hartes
August 2010