I also get very thirsty but I have a rather complicated medical history. I had a pituitary tumor removed in 2004. The tumor was sitting on the area that controls the concentration of urine. I ended up with a disorder called diabetes insipidus (NOT diabetes mellitus which is related to glucose). I have chronically high sodium levels and need to drink lots of water to counteract the effect of frequent urination. I take DDAVP but still do not have things under control.