That feeling of flatness is such an empty feeling isn't is. Thinking of you. I love Autumn too, it's my most favourite time of the year. I love the warm days that are fringed either side by cool morning and evenings.
The Autumn leaves are out in our local park, I took some photos yesterday, it was cool but beautiful. It looks like a beautiful week ahead here in Melbourne, enjoy. :)
I know that feeling - and just reading this made me feel it. Feels like you can't shake it. Enjoy your time in the garden, so pretty this time of year.