What should I actually do with my investments during a bear market?

For most long-term investors, the best action is boring: keep contributing on schedule and do nothing dramatic. Continuing to buy while prices are down means you're purchasing shares on sale, which lowers your average cost. Panic-selling locks in losses and, worse, usually means you miss the sharp rebound that often follows the worst days.

Concrete steps: confirm your emergency fund is intact so you're not forced to sell, keep automatic investments running, and consider rebalancing, selling some of what held up (bonds) to buy more of what dropped (stocks), which enforces buy-low discipline. If a bear market is destroying your sleep, that's a signal your allocation was too aggressive; note it and adjust after the storm, not at the bottom. Avoid checking your balance daily; it fuels bad decisions.