I think you should have a full work up by a GP and a gastroenterologist, and and perhaps someone who handles glands, and maybe have your thyroid checked, for both the thirst, and the desire to throw up when eating, or not eat. One possibility for the thirst that occurred to me is that perhaps you take in too much salt? As for your problem with food, you may have GERD, or some other stomach, throat, or esophageal problem. Do have a thorough check up for these problems, though.
I don't have your food problem, except for acid stomach and acid reflux, but I do tend to be thirsty, and always have, although not as bad as you. My earliest memories are of standing at the railing of my crib, dressed in those one piece outfits with feet on them, in the middle of the night. I would be swaying back and forth chanting "Mommy, Daddy, I want wawa." According to my memories, this happened often. I also had a continence problem, partly from stress, and partly from having taken in too much water, and not gotten to the bathroom in time. There have been phases of my life when I carried a water bottle around, but not lately. I now live alone, and can get food, water, and use the bathroom whenever I want at home. This is important to me as I also have IBS. I did have one terrible time when I lived with two other relatives in a one bathroom house. It was horrible.
I have greatly reduced my acid stomach/reflex problem by almost eliminating greasy foods from my menu, and by reducing stress. Living with relatives was very stressful, as were my financial problems. I now live alone, and am on disability, which pays my bills, so my stress has gone down.
My current incontinence problems are caused partly by getting too engrossed in whatever I am doing, by my being over weight (it puts pressure on the bladder), and sometimes by coughing or sneezing at the wrong time. I have to try harder to not get so lost in what I am doing, that I don't get to the bathroom on time. I can't do much about the other causes.
I was doing a search, and one possible cause of excessive thirst can be a zinc deficiency. You could try slightly increasing your zinc level to see if that helps, as it is supposed to help the body hold onto water better, and thus reduce thirst. However, only add a little to your diet. Although small amounts of zinc are necessary to us, too much zinc is toxic. Another site had more info, including more causes. It is:
http://www.buzzle.com/articles/excessive-thirst.html
Do some I-net searches of your own for excessive thirst plus no apatite. Please do get yourself checked out, as this does sound like it needs looking into.
Good luck.
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