I would imagine that you've found out what you have by now. It sounds like Addison's Disease in many respects, but no one can diagnose without a medical exam. I am not a doctor, either. You can go into Addison's crisis if you do have Addison's but there is treatment. I do hope that you are well.
Please disregard my last comment. You don't seem to fit exactly into any Addison's category other than the pigmentation of your skin. You may have some adrenal problems, but I am not one to say. The head heaviness can be from a variety of reasons including inner ear problems. My suggestion is to see an endocrinologist, since your problems seem more related to hormones from what I can tell. Also, considering your sinus problems, an ENT evaluation would be a good idea.