Quick word of encouragement: I scored 10 points higher on my September retake after a lower-than-average June perfromance. I was ready for the June test, but I psyched myself out. I only took five or so practice tests between June and Sept. I wanted to study more for the Sept. test, but I didn't want to get burned out again.
Moral of the story: If you were ready but under-performed, you might want to take an LSAT breather before re-studying, and, even then, you might want to take it easy.