Inny2009,
I'm sorry that you're having such a rough time.

Honestly, I don't know if the ANA test can rule out diseases like MS. I *think* that MS can be difficult to diagnose, as it often goes into periods of remission. I have taken care of several people with MS, as a CNA. I would advise you not to look too far into the list of possibilities.
So many different illnesses can cause different symptoms in different people. Really! I definitely understand your desire and thirst for understanding what's wrong with you. (I've been there myself, several times) BUT, I'd advise you to go to top doctors to find out what's happening.
Personally, I wouldn't even take cost into consideration. You need to take care of yourself. With these things getting in the way, you've got a major problem that needs to be figured out before you can start to worry about how you will pay the bill. You deserve to get answers to your problems.

Best wishes to you!