The plant looks really terrible. A few days i gave her an compost tea and top dressed her, i hope it helps.
I think it was my fault with the watering. Maybe she was to dry, or to wet, or maybe both.
I let her dry out and when shes completly dry and then we will see, but it looks like an potassium deficiency.
Terrible about your plant dying it does look like a cal mag deficiency but those little rust spots can also be a sign of an issue with your root zone it can be fungus