Each month, new My Room items are put into the Carpenter of Chance and MØBL. These items are given a multiplier for the month in which they are introduced. When a new event starts, all My Room items from the previous month lose their multiplier and your score will return to normal. Your score could also be decreasing because not enough new guests are visiting your room. It could also be because you have published and unpublished the room several times. Doing this causes your room to lose the points that it gained from being given room cookies.