Maybe over-thinking it a bit. Try and accept it as a paid rehearsal. Sometimes other things happen, maybe another event on locally. Do the next gig 20 mins away and see how that goes. Sounds like you've put a fair bit of work into this band and i dont hear any complaints from you about the band and its members so i'm guessing all good in that department. Not easy finding good guys to work with so stick with it a while longer.
We all have "down days", its part of being in a band. Let it pass and get back out there with a positive can do attitude and all will be well in "The Shire" again. 👍
Dave