don't try to force feed, it will only make matters worse...force feeding should be left for an absolute last ditch situation
I would agree that she is looking quite dehydrated. Based on your description of her poo, Snake's guess at a parasite is probably a good one. Whatever is causing the diarrhea is causing dehydration and likely stressing her in not eating.
I would add a fairly large amount of foliage to her cage (can you give us a full cage pic?)
Also, are you sure your temperatures are accurate? 100W Neo bulb generates a LOT of heat....I use a 60W standard incandescent bulb and have temps in the 80-85 range at my basking spot and 70-80 throughout the setup...with a 100W my temps would be WAY higher.
if you are keeping up on your care as listed, then i would not think it is a husbandry issue (minus the supplementation fix) but that would even further lead to likelihood of illness/parasite which would need a vet eitherway