It is about air circulation. Gym and mall has external air circulation while your hom air-cond is circulation internal air. This will make some people feel suffocate.

Basically this. Instead of just switching on air cond, switch on your fan too. With proper air ventilation, you can feel the same result even when you set your air cond's temperature to be higher by a few degrees, not to mention you save more electricity and you can breathe better.

I confuse. If too cold why you use aircond?

It will, as long as the stable air movement is 'disrupted' by the fan, the ventilation will be improved. Maybe put the stand fan under your air cond and point the fan blade upward if you can? See if it helps. Though, I was assuming, by 'feel sick', you mean you're having difficulty to breathe or something similar... So, your air cond might be faulty like others said if my assumption is wrong.

Not sure about any particular gym but shopping mall do not use air-cond system like home type. Like most factory, use system that circulate air from outsite by chilling it first before blowing it into the mall. THere are so many people and you need oxygen, otherwise you get suffocate with carbon dioxide. 

At home just few people and the oxygen requirement are less thus leak air even from under door pane is enough. I guess some people are more sensitive to lack of oxygen than others.

i think your AC  coil sensor  is faulty .  so your AC is running  much colder the 27  deg .

AC in some malls are  cold  definitely  temp less  than  27 deg .

Maybe you can consider switching on the air con for awhile just to cool the room, so leave it on for shorter periods of time