There is an old saying which says, "you have made your bed, now sleep in it", meaning you have set up or created the situation you now have and must now accept to live with it. This seems to apply to your dream since you did mention the blankets and the sheets which imply a made bed.
What the dream can be suggesting is that you might see yourself emotionally accepting a situation, that is that you might feel that you are accepting a situation. This is represented by the someone who has been in your bed. Yet because you were not the one in your bed, it would indicate that you really have not accepted to live with what you have set up for yourself. This also seems confirmed by the fact that not even the someone is now to be seen in the bed.
(Sorry I am not Tony but perhaps this will help you understand the dream.)