Is this grammatically correct? What does it mean? Any possible rephrasing? Some of us sleep, but we don't really rest because our minds are busy processing how to survive the next day.

Yes, the sentence is grammatically correct. It conveys the idea that while some people may be asleep, they are not truly resting because their minds are preoccupied with thoughts and worries about how to navigate the challenges of the following day. Here are a few possible rephrasings: 1. "Some of us may fall asleep, yet we never truly rest, as our minds are occupied with thoughts about how to make it through the next day." 2. "While some of us sleep, we don’t genuinely rest because our minds are constantly busy figuring out how to cope with tomorrow." 3. "Some of us might be asleep, but we aren't really resting; our minds are too busy thinking about how to survive the next day." 4. "Though some of us are sleeping, we aren't truly at rest, as our minds are engaged in processing how to manage the challenges of the coming day." Each of these alternatives maintains the original meaning while providing slight variations in expression.