To be honest it doesnt matter what it would look like because without a veterinary diagnosis you cannot begin any sort of treatment. Until you know what is wring, treat it as if it does have a condition.. since you dont know which yet you must be quite cautious.
This means ISOLATE it from any other lizards you own and wash your hands thoroughly after feeding/cleaning/handling the affected animal. If posible always handle your healthy animals BEFORE the unhealthy one to lessen the chance of spread.
Are the geckos eating? When is the earliest you can submit a sample to the vets?
Coccidia-infected feces often have some blood in it (dark red colour) ,stools are loose and smelly,with whitish pus dribbling from them.Also you can have a look under the belly of your gecko,the liver (blackish ,seen through the skin) will appear much bigger than it should be.
then mega-rush to a mega-vet on tuesday;this is the only thing to do...her behaviour going to the cold spot means nothing in particular.maybe raise your temps by a few °f,this will help the immune system of your gecko to work better :wink: