You probable pressed the Caps Lock button while holding down x. That will cause your snap to grid to stay on, even after you let go of x. What you need to do is turn off snap to grid on your status line at the top of your screen, then move your curser off the snap to grid button..the button will automatically turn back on. Just go up and turn it back off a second time...that should do the trick.
Don't be satisfied with what you can do but rather strive to do the things you can't do!