How do I write a mobile button that has different functions for if you are or aren't pressing it?

I'm trying to convert a sprint button that I successfully made on the shift button, work on mobile. When I just tap the button, it causes me walking, whether holding down the button or not, to cause sprinting. from what I can see it doesn't detect when the button is not being pressed as it continues to go through the repeat section.

function Sprinting(actionName, inputState, inputObj)
	if SprintAvailable == true then
	    if SprintAvailable and Stamina.Value > 0 and inputState == Enum.UserInputState.Begin then
				--Press to run
				print(BaseStamina.Value)
				print("Running")
				Char.Humanoid.WalkSpeed = RunningSpeed.Value
				--Start running chain
				repeat
					if Humanoid.MoveDirection.Magnitude > 0.1 then
						isPressed = true
			       		Char.Humanoid.WalkSpeed = RunningSpeed.Value
						game.Workspace.CurrentCamera.FieldOfView = 72
						Stamina.Value = Stamina.Value - 1
						Interface:Update()
						MainFrame.BackgroundTransparency = 0
						BarFrame.BackgroundTransparency = 0
					end
					wait(0.1)
				--Stop running
				until inputState == Enum.UserInputState.None or Stamina.Value <= 0
				print(inputState)
				print("Not running")
				Char.Humanoid.WalkSpeed = WalkingSpeed.Value
				game.Workspace.CurrentCamera.FieldOfView = 70
				--If stamina runs out
				--Revert sprint status
				if Stamina.Value <= 0 then
					SprintAvailable = false
					MainFrame.BackgroundColor3 = Color3.fromRGB(0, 0, 0)
					Humanoid.WalkSpeed = 1
					wait(1)
					Humanoid.WalkSpeed = WalkingSpeed.Value
					MainFrame.BackgroundColor3 = Color3.fromRGB(150, 0, 0)
					wait(5)
					MainFrame.BackgroundColor3 = Color3.fromRGB(0, 50, 100)
					MainFrame.BackgroundTransparency = 1
					BarFrame.BackgroundTransparency = 1
					SprintAvailable = true
				end
				MainFrame.BackgroundTransparency = 1
				BarFrame.BackgroundTransparency = 1
				while inputState == Enum.UserInputState.None and Stamina.Value < BaseStamina.Value do
					print("Reverting Stamina")
					Stamina.Value = Stamina.Value + 1
		       		isPressed = false
					Interface:Update()
					wait(0.5)
				end
		   	end
		end
	print(inputState)
end

print("ended sprint")

ContextAction:BindActionToInputTypes("Sprint",Sprinting,true, Enum.KeyCode.Compose)
ContextAction:SetTitle("Sprint", "Sprint")
ContextAction:SetPosition("Sprint", UDim2.new(0.7, -25,0.1, -25))

250

Running

Enum.UserInputState.End

Updating (x18)