I had my capacitor replaced 3 months ago after I discovered the compressor wasn't running. Everything worked well until this morning I woke up to a warm house and discovered the same problem...compressor not running. The air handler is running just fine but I noticed that A/C circuit breaker on the main house panel was tripped....and if I tried to reset it and turn the A/C back on it immediately trips the breaker again. I just really want my ducks in a row for what to expect so I don't get railroaded by the A/C guy.

Capacitors don't hold up like they used to. I know you don't want to hear this but its likely that your compressor motor windings are now shorted to ground or across the line which means big bucks to fix or replace. I have seen this happen many times that the capacitor failure causes damage to the compressor motor windings, a tech comes ot and puts a new capacitor on it and it runs a while then the compressor shorts out.
These compressors are hermetically sealed and the tech has no way to inspect or test them except for a meg-ohm reading. I hope I am wrong and the short turnes out to be caused by something else but be prepared for the worst. Good luck!