Created a rotation addon, but game freezes after combat / when I turn off addon

[Chas3down]

Whenever I turn off the rotation or when combat ends, my game freezes for like 5 seconds. if I was in combat for a longer period of time, it freezes for longer.

HunterRotation = LibStub("AceAddon-3.0"):NewAddon("HunterRotation", "AceConsole-3.0", "AceEvent-3.0")

local doRotation = false;

local blackArrowID = 3674;
local killCommandID = 34026;
local chimShotID = 53209;
local explShotID = 60053;
local multiShotID = 49048;
local killShotID = 61006;
local rapidFireID = 3045;
local readinessID = 23989;
local bestWrathID = 19574;

local blackArrowName = "Black Arrow";
local killCommandName = "Kill Command";
local chimShotName = "Chimera Shot";
local explShotName = "Explosive Shot";
local multiShotName = "Multi-Shot";
local steadyShotName = "Steady Shot";
local serpStingName = "Serpent Sting";
local huntMarkName = "Hunter's Mark";
local killShotName = "Kill Shot";
local rapidFireName = "Rapid Fire";
local readinessName = "Readiness";
local bestWrathName = "Bestial Wrath";
local bloodFuryName = "Blood Fury";

function HunterRotation:OnInitialize()
	self:RegisterEvent("COMBAT_LOG_EVENT");	
	HunterRotation:RegisterChatCommand("on", "On");
	HunterRotation:RegisterChatCommand("off", "Off");
end

function HunterRotation:On(input)
	print("On");
	doRotation = true;
  -- Process the slash command ('input' contains whatever follows the slash command)
end

function HunterRotation:Off(input)
	print("Off");
	doRotation = false;
  -- Process the slash command ('input' contains whatever follows the slash command)
end

function IsOnCD(spellID)
	local a, cd = GetSpellCooldown(spellID);
	
	if (cd > 1.5) then
		return true;
	end
	
	return false;
end

function TargetDebuff(spellName, onlyMe)
	local name;
	if onlyMe then
		name = UnitDebuff("target", spellName,nil,'PLAYER');
	else
		name = UnitDebuff("target", spellName);
	end
	
	if (name == nil) then
		return false;
	end

	return true;
	
end


function HunterRotation:COMBAT_LOG_EVENT()

	if UnitAffectingCombat("player") and UnitExists("target") then
		--if doRotation and (UnitHealthMax("target") - UnitHealth("target") > 0) then
		if doRotation then
			if not TargetDebuff(huntMarkName, false) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(huntMarkName);
				return;
			elseif IsShiftKeyDown() and not IsOnCD(rapidFireID) and UnitBuff("player","Rapid Fire") == nil then
				CastSpellByName("!Auto Shot");
				CastSpell(5, "pet");
				CastSpellByName(bloodFuryName);
				CastSpellByName(rapidFireName);
				return;
			elseif IsShiftKeyDown() and not IsOnCD(readinessID) and IsOnCD(rapidFireID) and IsOnCD(multiShotID)and IsOnCD(explShotID) and IsOnCD(chimShotID) and IsOnCD(killCommandID) and IsOnCD(bestWrathID) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(readinessName);
				return;
			elseif not TargetDebuff(serpStingName, true) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(serpStingName);
				return;
			elseif not IsOnCD(blackArrowID) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(blackArrowName);
				return;
			elseif UnitExists("pet") and IsShiftKeyDown() and not IsOnCD(bestWrathID) and not IsOnCD(killCommandID) then
				CastSpellByName("!Auto Shot");
				CastSpell(5, "pet");
				CastSpellByName(bloodFuryName);
				CastSpellByName(bestWrathName);
				return;
			elseif UnitExists("pet") and not IsOnCD(killCommandID) then
				CastSpellByName("!Auto Shot");
				CastSpell(5, "pet");
				CastSpellByName(killCommandName);
				return;
			elseif not IsOnCD(chimShotID) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(chimShotName);
				return;
			elseif not IsOnCD(killShotID) and UnitHealth("target")/UnitHealthMax("target") <= .20 then
				CastSpellByName("!Auto Shot");
				CastSpellByName(killShotName);
				return;
			elseif not IsOnCD(explShotID) and not TargetDebuff(explShotName, true) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(explShotName);
				return;
			elseif not IsOnCD(multiShotID) then
				CastSpellByName("!Auto Shot");
				CastSpellByName(multiShotName);
				return;
			else
				CastSpellByName("!Auto Shot");
				CastSpellByName(steadyShotName);
			end
		end
	end
end

Any ideas how to fix?