I have made a Stamina Bar. How do you make it decrease vertically?

Ok, so I have made a Stamina bar in Roblox Studio and it works completely fine. However, I want it to decrease vertically when the player runs, but it decreases horizontally when the player runs.

Anyway here is my script:

local bar = script.Parent

local stamina = 100
local staminaRate = 1


local plr = game.Players.LocalPlayer
local char = plr.Character or plr.CharacterAdded:Wait()

local humanoid = char:WaitForChild("Humanoid")


local isSprinting = false


local uis = game:GetService("UserInputService")


uis.InputBegan:Connect(function(key, gameProcessed)

	if gameProcessed or stamina == 0 then return end


	if key.KeyCode == Enum.KeyCode.LeftControl then

		isSprinting = not isSprinting

		if isSprinting then
			humanoid.WalkSpeed = 25
		else
			humanoid.WalkSpeed = 16
		end
	end
end)


while wait() do


	if stamina == 0 and isSprinting then

		isSprinting = false
		humanoid.WalkSpeed = 16
	end


	if isSprinting and humanoid.MoveDirection.Magnitude > 0 then

		stamina = stamina - 1
		wait(staminaRate)

	else
		stamina = stamina + 1
		wait(staminaRate)
	end


	stamina = math.clamp(stamina, 0, 100)

	bar:TweenSize(UDim2.new((1/100) * stamina, 0, 1 ,0), Enum.EasingDirection.InOut, 							Enum.EasingStyle.Quint, 0.5)
end