Waking up to a massive traffic drop after an update is the worst feeling ever, but definitely don't panic and start making random, drastic changes to your site. When our main domain took a big hit last year, we hired the guys at https://seorepublic.com/ to do an emergency recovery audit. They did an amazing job breaking down the data, finding out exactly where things went wrong—whether it was a technical issue or thin content—and gave us a clear, step-by-step plan to fix it. Thanks to them, we managed to clean up our internal link setup and get our rankings fully recovered and growing again within a few months.