Open the doors and look at the hinges very closely. Look at a bad one and look at a good one - if there is a good one - if they are all bad then go next door and look at your neighbours - or to the Kitchen section of a DIY store - theirs will be on the level.
Try to work out what's happened to your crooked doors - and rectify it.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix general d.i.y.