My WordPress site became extremely slow overnight

This is super frustrating but honestly pretty common. First thing I'd do is check your hosting provider's status page — sometimes they have outages or maintenance that tanks performance. If that's clear, the most likely culprit is a plugin or theme update that ran overnight. Even auto-updates can break caching. Try disabling all plugins temporarily and switch to a default theme like Twenty Twenty-Four to see if speed returns. If it does, re-enable plugins one by one to find the offender. Also clear your cache (both server-side and browser), check if you have a CDN like Cloudflare and make sure it's not misconfigured. Another thing — check your database size. Sometimes a bloated wp_options table from a bad plugin causes slow queries. You can clean that up with a plugin like WP-Optimize. Finally, run a GTmetrix or PageSpeed Insights test to get specific diagnostics. That'll tell you exactly what's slowing you down.