When I started up a world like normal I pressed the "W" key , After taking my finger off the button I still moved forward with no control over the keyboard or the mouse for at least 20 seconds this problem persisted until I quit Minecraft . This also happened when mining . After a few hours I tried again , same thing happened. I tested if this happens in other games such as TF2 , I got nothing , so that tells me that this is a problem with Minecraft itself.