I've had almost all of those things- the headaches, the digestive issues, and hair loss. Before being diagnosed, for years I ended up in the ER with severe vomiting and stomach pain, for absolutely no reason at all- not eating horribly,etc. It would last for about 24-36 hours and drain the life out of me. Usually including an upset stomach of the other variety as well, so really not fun. There was no pattern to it, except that stress was a factor. It would start pretty suddenly. I could wake up feeling fine and a few hours later, I was gray and on the bathroom floor. All the tests were negative, but since being diagnosed with lupus and being on a regimen on cell cept (pred in the beginning), and adding plaquenil and keeping the disease in check- I haven't (knock on wood) had even ONE episode in over a year and a half. That's amazing for me. It used to really make me feel like it was controlling my life- it was crazy, and it was jeapordizing my job at times too- I was miserable. So hopefully when they can diagnose you, they can get it under control systemically, and not try and control it symptomatically- which only went so far with me.
The hair, I lost over half of it. And it's really taken about a year and a half for it to really start looking normal for me again. But if I have any advice- don't be like me and hold onto longer hair when it gets thin. I cut it short and it looks much better :o)
As for headaches, now I'm on topomax, and for the most part they're under control. But it's not hard to get one- sun is the biggest culprit.