I obsess as well, but I never sell. I've been putting money in since 2003 and have only sold occasionally to reallocate. I recently dumped everything in my IRA's to go to a simpler, lower cost model, but that was planned and I didn't leave the market for more than a day (luckily the market dropped that day so it worked out for me. Also, the non-retirement account is waiting for my retirement, so I can drop below the 15% income tax bracket and get free cost basis reset)
I read an article on how the 2008 crash and subsequent market recovery increased the wealth disparity by huge factors. Of course it did... Some people paniced and sold at a 40% loss and stayed out. I did some math on my personal accounts. I watched my portfolio drop 35% (like 80k at the time), shrugged, kept my allocations rolling and saw a ~4.0x gain in the subsequent 5 years. The stock positions are up ~9% since 2003 (which includes the crash of 2008, but obviously not the 1999-2000 crash) and the overall account has grown on average 19% a year overall, and 24% a year for the last 3, including the money I've been shoveling in.
So obsess all you want, update your FIRE tracker, blah blah, but don't depart from your course. Stay in, dollar-cost-average, and don't panic.