If you're that thirsty, you should be checking your blood sugar frequently (I'm sure you know this). Fatigue is such a vague symptom that it's really hard to figure out what is causing it if you are already experiencing a multitude of health problems (and, of course, even healthy people get fatigued when they are stressed).
Can you elaborate on the med your doc gave you? Diphenhydramine/atropine?
How's it going today, Janet?
Try that Lomotil if you're having diarrhea, it works like a charm (although I found Immodium to be just as effective and cheaper).
Are you adjusting to the stress at all?
That's great the Lomotil helped you out today. You know you're certainly not alone in the anxious/depressed department NOR the diarrhea department! It's rough and I can sympathize. I just moved across the country for med school and am experiencing various states of major anxiety/denial/homesickness/you name it. I had my first migraine in about 10 years last night and puked all over the place, and then had diarrhea like 10 times today. It's been a BLAST (in more ways than one, LOL).
Just hang in there. Remember you're not alone, you've got lots of comrades here.