Hi, Ilia,
For more support when sitting at your desk a high-backed chair is a very good thing. As the window is only behind part of your back, a picture of a mountain behind you maybe a good idea.
In my office I have the same situation with window and door. If you have the feeling that the energy is rushing through the room then you can try different things to draw the attention away from the window, maybe pictures on the wall or a sitting area (depending on the size of your office, of course) or a table where you display your products etc. I rearranged my furniture and tried to give enough room for the energy to gather. When I enter the room my attention is no longer attracted by the window, there is enough free space and I feel good about it. Maybe all you need is a little rearrangement of the furniture in your office. Sometimes nice plants are a good idea ...
Love,
Astrid