Any and all apps crashing is not something I've heard of before. Did anything happen before it started, e.g. installing or updating any apps, system update (very unlikely if you are running Android 5 still!), any other strange behaviour of the device?
All I can suggest is a generic "go into recovery, wipe the cache (just the cache) and reboot" and see whether that helps.
Maybe also wipe your launcher's cache for good measure.
If none of that works, try booting into safe mode and see whether it's any different. If things work in safe mode but not in a normal boot then (somehow!) one of the apps you installed is the problem.