my clowns are not eating anything(2 days).
How long have you had them? If they are new...this is not uncommon. Are they wild caught or tank raised?
open-mouth gasping.. lying on the bottom.
This is not good, could be ich, velvet or brooklynella, hard to say without a pic or a better description of their physical appearance.
A little cool, I would bring it up to 80-82 over the course of a few days.
How are you measuring your salinity? If your useing a test lit or a refractometer and measuring in ppt, then your salinity is a little low, natural reef salinitis are around 35ppt @ 82-84*F. If your using a floater or a swing arm hydrometer are you using the ppt reading (worthless on this type of unit) or are you measuring the specific gravity and you mean 1.028, 1.028 would be a little high as 35ppt roughly corresponds with 1.025 @82-84*F.
I'm gonna go out on a limb and say I think your dealing with brooklynella hostilis, do the clowns appear as if they have a slimey film coming off their bodies? does it look like their skin is coming off?