Since this started at the end of summer, and I see your plant is on the floor, that might be too cold while it's really cold outside. Aglaonemas are not interested in getting chilled at all, and the air near the floor is usually quite a bit colder. I try to keep plants on some kind of riser, even if it's only a few inches.
From the angle of the leaves, it does look like it could use a bit more light. When light is sufficient, leaf tips point up, which is their natural, healthy angle, as all of the pics in the DB entry for 'Silver Bay' show. I'm not sure that's your exact cultivar, but a diff name wouldn't have a diff growth habit.
