Its pretty simple to me...I suspect the problem is not a really bad sound, but a sound you don't like. Equally important but not as much of a disaster.
if you can get a good sound at rehearsal through a PA system at volume, then it was the venue/sound guy. therefore don't over think it, play the long game and work with the next venue sound guy.
Get there early, explain the problem you had and get his opinion. If the sound is the same and you don't like it but he does, then its your view of your sound. So sound isn;t bad, just not your taste. If he doesn't like it then you know there is a real problem.
If it sounds good, then its a one off...
In short, don't panic and make massive changes based upon this one experience