My animation is not working correctly, how do i fix it?

So, I just created my first animation and it is for a shotgun. I want it to work and it does but when you test it and your character moves in anyway, it stops the animation. Also, on the right hand where the shotgun is, the animation doesn't effect that arm. I know it is possible to fix this and make it all work and if interrupted keeps going, I just don't know how. Help please?

if Module.ReloadAnimationID ~= nil then
    local ReloadAnim = Instance.new("Animation",Tool)
    ReloadAnim.Name = "ReloadAnim"
    ReloadAnim.AnimationId = "rbxassetid://"..Module.ReloadAnimationID
end

(HERE IS THE SCRIPT THAT TELLS THE OTHER SCRIPT WHAT ANIMATION TO PLAY)

ReloadAnimationID = 3454070674; --Set to "nil" if you don't want to animate

I think it may be possible to modify the script so if an animation happens besides the reloading animation, the reloading animation will not stop.