I had to chuckle when I saw your note because I just went through the exact same thing and it's not fun!
First, to put into context, I live in the DFW area and today we are having our 11th consecutive day exceeding 100 degrees. Fortunately, a "cold front" is coming through on Saturday and we will only be in the low to mid 90s. Being a transplant, I always laugh when a summer cold front comes through and the temperature drops to low 90s.
Back to my issue.....Monday evening came home and everything was fine on the main level. But then I went upstairs and it was hot, with the thermostat showing 93 degrees. After doing some checking, I ultimately made some calls, and after trying a handful of companies, I was able to get someone to come out yesterday.
Fortunately, we have two units (one for downstairs/one for upstairs) so we were able to spend the majority of our time downstairs.
Luckily, only the compressor was out, so about $400 and 10 minutes later it was fixed. The unit is 11 years old, so I was fearing the worst...but I know that time is in the near future. STAY COOL!