The long and short of it:
Writing a short story is like running the 100 meter dash, while writing a novel is like running a marathon. Though some of the mechanics are the same, there are differences in training and mindset. Some people can do both well, but not all.
When you’re running a marathon, you have to ignore the cramps in your side, the pain in your feet from the constant pounding against pavement, you have to figure in hydration and nutrition. You must pace yourself correctly, and even if you’ve calculated a strategy before hand, it usually requires some adjustment as you go. The psychological experience is drawn out, and the biggest challenge can be to outsmart yourself.
I recently took a break from my novel length WIP to focus on a couple of short stories. Now I’m having difficulty switching back to the novel. My pace was disrupted, and I am finding I need to warm up to the novel again. Though I’m happy with the short story I produced, I don’t know if it was a good idea for me to switch. I only hope that I can get back up to speed quickly, but so far it’s been painful.
Do you work on multiple projects at once? Are you working on short fiction at the same time as long? If so, how do you switch between them?