I used to get pretty depressed in the winter months. I live in valley between mountains in Canada, so our winter is cold, long, dark and blanketed in heaps of snow for months. I try to focus on the good parts of these seasons, the trees changing colour, the crisp fresh air, halloween, first magical snowfall of the year, hot cocoa, fires, christmas etc. I have taken up winter sports like snowboarding, skating, sledding so that I don't feel trapped in by the cold and snow. Otherwise that is depressing.

I tend to go way way overboard at halloween and christmas with the decorating and such but it gives me something to focus on that lifts my spirits. It's simple I know, but simple thigs in life can be very good

Perhaps trying not to focus on the traumatic things that have happened,just letting them go and live in the past while you remain in the present and focus on now. Try to let these seasons remind you of something new. It may help to find new things to associate these season to
There is some beauty in winter, the earth starting a new cycle of life. But I always fonding not letting the past predict the future to be very helpful, and sometimes we almost recreate it out of stress and worry, anxiety.

I hope you will have a better experience this fall and winter. You could try a light box or a dawn simulator like Bipolarnurse mentioned. I know many people have talked about how helpful those have been for them. I can really see why they would help.