Something to consider, law schools will assume a canceled score is a low one. Keeping the low one and retaking later on can show a lot of growth as well, especially if you're scoring much higher the next time around when you're more prepared.

The first time I took the LSAT was under similar conditions, I was working 70+ hours a week and working nights on top of my day job. I performed very poorly, even in comparison to my diagnostic test. My advice isn’t really about how to maintain studying with the lifestyle because I wasn’t able to, I had to take a step back and sacrifice some things so I could have the time I need to increase my score.