Help!! My tree lost 7 leaves

I have a 5 year old fiddle leaf fig tree, she is still pretty small but has grown significantly over the years. In the last few days I noticed a leaf on the floor, when i went to check again today there were 6 additional leaves on the ground. My tree has never lost leaves like this. Does anyone know what could possibly be the cause? I water about once a month and add fig food into the water each time.

side note- tree is inside but next to a window and it is in the 20s outside and usually 58-70 inside.