If you haven't heard of the Four Noble Truths for writers, you'll find them (and more) in Gail Sher's book on writing, One Continuous Mistake.
The Four Noble Truths are:
1. Writers write.
2. Writing is a process.
3. You don't know what your writing will be until the end of the process.
4. If writing is your practice, the only way to fail is not to write.
Implicit in these noble truths is the idea that in order to write, writers must accept mistakes.
Also implicit is the idea that one cannot expect the words to appear perfectly on the page the first time they emerge from your pen.
As one of my teachers, Phyllis Root, used to say (and perhaps still says): "Writing is a messy business."
The process isn't linear. Not all the time, anyway.
You may pursue a narrative thread one day, only to lose it the next day... and find another thread the day after.
By the end of the week you may find yourself weaving together threads that weren't even visible when you began.
As Sher suggests, you won't know what your writing will be until the end of the process.
Each day you may have to find a different path to the place where you need to be that day.
And part of the writing process is struggling to find that path before you can find the words.
But remember Sher's advice: "the only way to fail is not to write."