Having said that, let me be most helpful to you by being very honest. Let's forget for a moment everything about kua numbers, best feng shui directions, etc, etc. Why do you think your life is a total disaster? What elements, or categories, make it so? I would suggest you spend some time making a list and really clarifying the issues at hand to the best of your abilities. Take your time with it, but also make an "alternative" column, which will list what makes you life a total blessing, too, as one cannot be without the other!
After you have a better/clearer picture as to which areas of your life are working and which ones are crying for attention, look around and see what is happening in your space on a very basic level. Better yet, ask a good friend to honestly give you feedback as to what is happening in your space, especially in your bedroom. You will need a real friend to do this with, as the more honest the feedback, the more helpful, be ready to take in as much hush criticism as possible.
After you have done a thorough "scanning" of your space, taking care of every detail that surrounds you - the messages your items are carrying in terms of colors/emotions/their state of being, the possible cluttered spots, etc - and adjusting them properly; you can move on to a bit more advanced levels of feng shui. I cannot emphasize this point enough, as I see it very often in my work -there is something about our Western culture where we tend to over-intellectualize and not see things that are right in front of us screaming out loud for attention!
And yes, you should definitely strengthen the North area, as it is connected to your career success. Both Water and Metal element colors are good there, as well as images/items connected to the growth of your career and overall, your growth as a human being on this earth.
It is NOT a good direction for you in terms of sleeping (the direction the crown of your head points to) or facing when you work; and this is where, I think, the confusion started for you.
Many Blessings and Best of Luck!