There are 2 different kind of ammonia test kits. One with Nessler Reagent (1 bottle) which goes from clear to yellow.
Another one is Salicylate method (2 bottles) which goes from yellow to green.
Thus depending on which one, will show different colors.
As Byron stated, high ammonia at pH lower than 7.4, no need to panic.
As far as levels increasing, cant say for sure but DO NOT vacuum gravel nor disturb the filter during such mishap. By disturbing, you are probably reducing amount of benefial bacteria.
Simple, small but frequent water change and controlled feeding shoud reestablish this tank with time.
As long as nitrite is registering, tank is going toward right direction.
Just have patience and try, if possible
, to keep pH lower than 7.4, until at least ammonia is well under control. What is pH of your tap?