toyota SA53 RS2000 sewing machine clutch problem? ?

I use the above machine regularly and it has been an excellent workhorse. It is only 3 or 4yrs old but I have probably used it to do heavier work than it is meant for. A couple of days ago whilst doing very 'heavy' mending it seemed as if the clutch was slipping and the machine is now unusable as cannot drive needle through any material. Is this something I could adjust or mend myself or would I have to take it to a proffessional?