Last week I noticed my AC had stopped working and as it was getting hot I was a little worried. Yesterday I purchased some refrigerant and low and below it was empty. I charged it and immediately had cold air. Today I got in the car for the first time at around 5PM and couldn't get any cold air, it was hot again. I hooked the pressure gage up and it shows that is fully charged(pissed) . Anyone have any advice? It is hot this week and can't afford to take it into the shop, so I hope someone has the answer. Thanks a lot.