How do I fix my sprinting animation playing while player is standing still?

Basically, I have a sprint script which works well but whenever I hold the LeftShift the animation starts playing when the player is standing still.

Things I tried: Detecting when player is holding the W key, detecting player velocity, detecting if the HumanoidStateType is idle (there's no idle state)

Code:

local UserInputService = game:GetService("UserInputService");
local player = game.Players.LocalPlayer or game.Players.PlayerAdded:Wait();
local PlayerGui = player:WaitForChild("PlayerGui");
local Stamina = script.Parent:WaitForChild("Stamina");
local camera = game.Workspace.Camera
local Character = player.Character
local Anim = Instance.new('Animation')
local Humanoid = player.Character:WaitForChild("Humanoid")
Anim.AnimationId = 'rbxassetid://myid'
local PlayAnim = Character.Humanoid:LoadAnimation(Anim)
local cool = false;

UserInputService.InputBegan:Connect(function(sprint)
	if sprint.KeyCode == Enum.KeyCode.LeftShift then
		if not cool and (not player.Character:FindFirstChild("Stun")) then
			coroutine.wrap(function()
				cool = true;
				wait(0.85);
				cool = false;
			end)();
			wait(0.65)
			player.Backpack.Running.Value = true;
			PlayAnim:Play() -- plays the running animation
			return;
		end;
	else
		return;
	end;
end);
UserInputService.InputEnded:Connect(function(keyPress)
	if keyPress.KeyCode == Enum.KeyCode.LeftShift then
		player.Backpack.Running.Value = false;
		PlayAnim:Stop() -- stops the running animation
	end;
end);
local pog = false;
while wait() do
	if Stamina.Value > 0 and player.Backpack.Running.Value == true or player.Character:FindFirstChild("Stun") then
		local Humanoid = player.Character:WaitForChild("Humanoid");
		if Humanoid.MoveDirection == Vector3.new(0, 0, 0) then
			script.Parent.regenStaminaClient.Disabled = false;
		else
			script.Parent.regenStaminaClient.Disabled = true;
		end;
		Humanoid.WalkSpeed = 22; -- sprint walkspeed
		local playerStats = PlayerGui:WaitForChild("playerStats");
		if not pog and Humanoid.MoveDirection ~= Vector3.new(0, 0, 0) then
			Stamina.Value = Stamina.Value - 1.25;
			playerStats.Frame.Stamina.Bar:TweenSize(UDim2.new(Stamina.Value / 100, 0, 1, 0), Enum.EasingDirection.Out, Enum.EasingStyle.Linear, 0.1, true); -- tween stamina bar
			wait(0.1);
			pog = false;
		end;
	elseif Stamina.Value <= 0 or player.Backpack.Running.Value == false or player.Character:FindFirstChild("Stun") then
		local Humanoid = player.Character:WaitForChild("Humanoid");
		player.Backpack.Running.Value = false;
		PlayAnim:Stop() -- stops the running anim
		Humanoid.WalkSpeed = 16; -- goes back to normal walkspeed
		script.Parent.regenStaminaClient.Disabled = false;
		end;
	end;