You are thinking about this in entirely the wrong way, and you will be poorer and worse off because of it.

Plow as much money into your 401(k) as you can every paycheck no matter what, but super extra especially while the stocks are on sale. Buy cheap globally diversified index funds. Stop monitoring and thinking about it, because that is how you make yourself poor.

Your balance doesn't matter for another 30+ years. Stop thinking about it and buy more.