Why are my animations so jittery upon being played?

This animation handler that I have works without returning errors however, when the animations are played, they stutter as if being started over 4 or 5 times before playing. I just want the animations to play normally and when they are called.

Now, when I don't stop all animations being played in the humanoid, the animations play infinitely over the idle animations (Even while using animtrack:Stop()) , but when I do stop them all, the animations begin to jitter and shake. Taking a few moments to play in most cases. Please help if you can, thanks!

See line 66

--Player Variables--
local Left = Instance.new("Animation")
    Left.Name = ("Left")
    Left.AnimationId = "rbxassetid://416628708"
    local Right = Instance.new("Animation")
    Right.Name = ("Right")
    Right.AnimationId = "rbxassetid://428103166"
    local Forward = Instance.new("Animation")
    Forward.Name = ("Forward")
    Forward.AnimationId = "rbxassetid://416928312"
    local Backward = Instance.new("Animation")
    Backward.Name = ("Backward")
    Backward.AnimationId = "rbxassetid://416928338"
    local Jump = Instance.new("Animation")
    Jump.AnimationId = "rbxassetid://408621791"
    local Idle = Instance.new("Animation")
    Idle.Name = ("Idle")
    Idle.AnimationId = "rbxassetid://416928266"
    local Sprint = Instance.new("Animation")
    Sprint.AnimationId = "rbxassetid://409050900"

    local already_ran = false
    local grounded = false
    local State = false
    local RunningDebounce = false
local P = game:GetService('Players').LocalPlayer
repeat wait() until P.Character
local Inputs = {Left,Right,Forward,Backward,Jump,Idle,Sprint}
local Event = game.ReplicatedStorage.Events:WaitForChild("AnimationEvent")      
local Value
local Walkspeed = script.Walkspeed.Value
function playAnimation(parent)
        local AnimTrack = P.Character.Humanoid:LoadAnimation(parent)
        AnimTrack:Stop()
        wait(.01)
        AnimTrack:Play()
        --AnimTrack:AdjustSpeed(1.5)
    end

function onKeyPress(inputObject, gameProcessedEvent)
    --if State == true then
    if inputObject.KeyCode == Enum.KeyCode.A then
        Value = Inputs[1]
        Walkspeed = 12
        elseif inputObject.KeyCode == Enum.KeyCode.D then
        Value = Inputs[2]
        Walkspeed = 14
        elseif  inputObject.KeyCode == Enum.KeyCode.W then
        Value = Inputs[3]
        Walkspeed = 12
        elseif  inputObject.KeyCode == Enum.KeyCode.S then
        Value = Inputs[4]
        Walkspeed = 10
        elseif  inputObject.KeyCode == Enum.KeyCode.Space then
        Value = Inputs[5]

    end
end

game:GetService("UserInputService").InputBegan:connect(onKeyPress)

    P.Character.Humanoid.Running:connect(function(speed)

        if speed < 1 then
        for _,v in pairs(P.Character.Humanoid:GetPlayingAnimationTracks()) do v:Stop() end
        playAnimation(Idle)

        elseif speed > 0 then
            for _,v in pairs(P.Character.Humanoid:GetPlayingAnimationTracks()) do v:Stop() end
            playAnimation(Value)
            --local e = game.ReplicatedStorage.Events.WalkspeedEvent
            --e:FireServer(Walkspeed)
            print(Walkspeed)
            wait(0.1)
        end
        end)