It seeps in from somewhere unknown and fills in every part of your veins. You can feel the pain and the sorrows in your heart, weighing it down as if it is feet that are chained with heavy metal spheres. You are shivering from how cold it is to not have anyone holding your hands and telling you things will be fine. You can see the world going on, and people living their lives but for some reason, you cannot do so. Your bones feel like they are fragile and will break if you decide to leave and see beyond your bedroom. Loneliness has no mercy and can keep leaving and coming back as if its a friend. It makes you addicted to it, while you know it is a drug that can slowly kill you. It makes you back away from people because love is the cure and it does not want to be cured. It wants you to crave it and be all over you, through your bones and skin, through your blood and in your mind.
It is a skilled demon, but it usually loses in its battles. Fight it.