Hopefully someone else started compressions immediately (unless you knew ahead of time the owner did not want CPR) when you went for the doctor. If nobody started compressions until the doctor was found - that's a much bigger mistake.
First and most important rule for a patient that drops - check for a heartbeat and start compressions unless you're sure you have heart function. Always always always. The doctor is (way) less critical than compressions. Unless my staff have a person who truly isn't doing anything, they don't send anyone to get me until they've begun compressions, established an airway, and are hooking up monitoring.
Reason? They don't need me to do anything except say "give drugs" and then call the owner, which doesn't happen until that other stuff is done. They certainly don't need me to say "start compressions".
(In your case, it almost definitely wouldn't have mattered or changed the outcome - but you can never really be 100% sure of that.)
Just remember you couldn't have changed anything. Sucks, but they usually die. And having the presence of mind to get help - even if you ran instead of yelled - is a good thing in general.