Why is my scion xd 2008 vibrating.?

The scion has 40,000k miles on it with no major issues up until now. When I take off from a stop light or sign or when I shift from 1 to 2 or 2 to 3 while letting off the clutch and slowly accelerating it vibrates the car. Also sometimes when I push the clutch in I can feel it vibrate a bit. The way I can best explain is is when you pull a rubber band and you feel the elastic vibrating as it gets longer thats kind of what it feels like, if that makes any sense. Any insight would be nice. Thanks in advance.