Macbook Pro Screen falling off Unibody cover?

my macbook pro screen has started to fall off the unibody cover recently.. when its open you cant tell, however when you close it you can tell that the left side of the screen comes out of the unibody cover and its getting worse and worse to the point that i can now stick my finger something in between the cover and the lcd screen...
does anyone have any idea how to fix this?
also when i close the macbook pro i have to push the side down for it to go down a little more but still not all the way.