Write what you know. This is the first bit of advice my sister muses and I offer an aspiring writer. But what if "what you know" is painful, traumatic, or just plain sad? What if you are unable to write what you think you want to write because of difficult times in your life? For the writer, bad times can become a wellspring of inspiration...and maybe you can help others who have suffered through their own unique troubles.
I'm not a philosopher. I leave that to others. My job is to inspire my writer to write. Sometimes, though, life interferes. Illness, accident, family emergencies...anything that demands full attention can stop a writer in her tracks. If your mind is consumed with a life-altering situation, how can you devote even a small amount of time to something that seems trivial, like writing fiction?
The answer is simple. You must write because you're a writer.
I'm not suggesting a tell all where you recount every detail. While that may be therapeutic for you, it rarely results in compelling fiction. But taking your feelings and emotions and allowing your characters to experience them will give them more depth. And the reader will experience them, too. This is a real motivator to use bad times in your fiction. You never know how you may touch a reader, or even help them through their own bad times with your story.
You don't even have to use your unique situation. In fact, it might be better if you don't. Your feelings may be too raw. Using a different set of circumstances can give you distance that will allow the creative process to flow more easily. Bad times won't leave you in the frame of mind to pen a light romantic comedy. So, you may need to change gears. Start a new story. Create new characters who are facing bad times.
The main thing is, don't let bad times keep you from writing. Take the pain and use it to heal yourself and touch your readers' hearts.