So, first off I am going to preface this, but there’s no need to do this on Tick.
You can make this an event based system.
Regardless, what’s probably happening, is that bool “Attacking” is being reset to False.
Instead of doing your crazy tick damage thing and overlap setting your health. Use EventAnyDamage for your Character first off.
https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/Events/
And then use ApplyDamage to actually apply the damage On Overlap. Apply Damage | Unreal Engine Documentation
Watch this tutorial, should help you understand better:
