It seems to me like you've gotta get back to your roots like i had to do a few years back. i was going through the same thing...well, at least as far as the mental game went, and inspiration came from an unlikely thing. what you've got to remember is that your attitude toward bowling is a huge part of the game. you've got to realize that maybe it's nothing more than your attitude and mental game that's getting in the way of your scores increasing. do yourself a favor and try to observe kids bowling. the younger the better. watch how excited they get over nothing at all, over throwing a gutter. they get excited over being able to do what they're doing. you've gotta to look within yourself and ask why you started bowling. did you start because you love the game, and appreciated the little things? or did you start bowling to score well? if you started the game to bowl well...then quit, because you'll never be as good as you think you should. appreciate and respect the game, and you'll see better scores, and a clearer mind.
just my opinion. i hope it all goes well whatever you decide to do.
Matt