If you can't remember anything that was done to the car recently that may have caused this, and you think it could be driveshaft, then you need to get it onto a lift and have the u-joints inspected. If they are ok, other mounts and attachments should be inspected. If nothing is found, the wheels should be re- balanced (a weight could have fallen off). Whoever is doing this work should have road tested the car with you beforehand so that they know what they are looking for. 
WMD
WMD
