You might be suffering from seasonal affective disorder where you get depressed in the fall as the days get shorter because your brain isn't getting enough light.

The first thing to do is get full spectrum lights for your home, and sit in front of them early in the day to replace the lost light. You want the light to get to your eyes without it being pointed at them so it gets to your brain.

Another cause of SAD [seasonal affective disorder] is low melatonin levels so supplementing with it is very helpful. I started taking more melatonin a couple of years ago after reading this as I've had SAD for 25 years now, and was amazed at how much less severe the depression was with that and the full spectrum light.

Here's an article on using melatonin for SAD:

https://www.sciencedaily.com/release...0501113832.htm