My Camera Drag script keeps resetting back?

local ScreenGui = script.Parent
local ImageButton1 = ScreenGui.ImageButton1
local ViewportFrame = ImageButton1.ViewportFrame

local Camera = Instance.new("Camera")
Camera.Parent = ViewportFrame

ViewportFrame.CurrentCamera = Camera


local Part = ViewportFrame.Part

local ButtonDown  = false

local OldX = 0
local OldY = 0
local Z = 5


local Mouse = game.Players.LocalPlayer:GetMouse()




ScreenGui.ImageButton1.MouseButton1Down:Connect(function()

    ButtonDown = true

    OldX = Mouse.X
    OldY = Mouse.Y

end)


ScreenGui.ImageButton1.MouseButton1Up:Connect(function()

    ButtonDown = false


end)




local iX = 0
local iY = 0

Mouse.Move:Connect(function()


    if ButtonDown then
        --Left or X
        if Mouse.X < OldX then
            Camera.CFrame = Part.CFrame  *CFrame.Angles(0,iX,0) * CFrame.new(0,0,5) 
            iX = iX + math.rad(5)
        end

    end

    if ButtonDown then
        if Mouse.Y < OldY then
            Camera.CFrame = Part.CFrame *CFrame.Angles(iY,0,0) * CFrame.new(0,0,5) 
            iY = iY + math.rad(5)

        end
    end


end)

It keeps resetting and i was wondering if the error came from

            Camera.CFrame = Part.CFrame  *CFrame.Angles(0,iX,0) * CFrame.new(0,0,5) 

and

            Camera.CFrame = Part.CFrame *CFrame.Angles(iY,0,0) * CFrame.new(0,0,5) 

Does anyone know how I can replace CFrame.Angles(0, x ,0) to a normal value so it dosent reset everytime