Q.Why Are My Fig Tree Leaves Dropping?
I have bought this Chicago hardy fig tree about two weeks ago and transplanted it to a container. When I got it, it had only two leaves and is now growing more. I water it regularly depending on how the soil feels. For the last two days, I have noticed that some leaves have drooped. They have small brownish specks, and wondered if it was fig rust. But can’t be sure. We did have particularly hot/humid two days. I live in Ottawa, hardiness zone 5A.

Certified GKH Gardening Expert
That is Cercospora! This can be controlled, relatively easily, with fungicide sprays and good sanitation.
Here are some articles that will help:
https://www.gardeningknowhow.com/plant-problems/disease/cercospora-leaf-spot.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/special/organic/biofungicide-information.htm
https://www.gardeningknowhow.com/garden-how-to/info/homemade-fungicide.htm
https://www.gardeningknowhow.com/edible/fruits/figs/how-to-grow-figs.htm