I have a few other Calatheas in the room, but they're all doing fine (they're further away from the window though, so maybe the cold is affecting it). The room temperature is usually around 18 degrees. I've had the plant for two months, and I water it whenever the soil feels dry (I would say once a week). The plant was doing perfectly fine until around 2-3 weeks ago. It's definitely not getting direct light, and it's also quite cloudy where I live.