Hi She,
One question and a comment here. First-
Do you feeling you havent been able to eat due to a choking sensation when you try? Or just loss of appetite all together?
Second-
ER doc's unless you come in with a full panic or something they "see" wrong, will just send you out the door most of the time. Also, if you suggested the IV to them, they would dismissed it just as fast. The best way to approach this situation is to see your regular doctor, explain you haven't been able to eat, losing weight, and loss of thirst. Casually state you feel, this is becoming unhealthy that you are concerned, but fear that you may have dehydration. Don't mention getting or wanting an IV. The doctor will test you then for dehydration, probably run a few blood tests, just to rule out anything else. But the point being, You will be taken more seriously.
God Bless,
Trish