I'm an "elder millennial" by most definitions :-)
I'm not mourning the death of this bull market... in a way it's a relief to know that all the prognosticating about when it will come to an end will finally come to an end. It's also nice to be able to buy more shares each month with the same amount of money.
A few things I absorbed from the Great Recession and dot-com bust (which happened right when I was first beginning my savings)
Ignore the talking heads and prognosticators. Every recession is filled with noise about how THIS TIME IS DIFFERENT!! Sure, no two situations are alike, but we've survived world wars, cold wars, fascism, genocides, energy crises, and far more just in the last 100 years
When markets are this volatile, concentrate on the number of shares you own in your index fund(s), not the latest purchase price. Eventually the market will recover, prices will go up, and in the meantime your periodic purchases will buy that many more shares.
This will change the future in ways that are hard to predict now. Many of these changes will be for the better, or to reduce the risk of this particular thing happening again. That is a good thing
The market is not the economy, and the economy is not society. Remember that when people are predicting "the end of days" - they are talking (in hyperbole) about the market, not the economy or society
Ultimately the economy is a collection of transactions that involve people. People will need to buy and sell things, and we are a community-driven species. From every economic crisis a new economy is born, because there can be no other way.
Our system is hardwired to go through boom-and-bust cycles. We get overconfident and underprepare during the boom times, and then opportunities crop up during bust cycles that drive the next boom. Correlation: an absurdly large number of wildly successful startups all began during recessions. It seems that recessions breed better (or at least more disruptive) businesses, while boom times generate more risky behavior.
just a few things to consider.
ETA: changed a few words for clarity, grammar.