Where do you find the discipline to write every single day?
You make a choice: you choose to write today, or you choose not to write.
If you didn't have time to write today, you've still made a choice. That choice was to put writing low enough on your list of the day's priorities that it didn't get done.
And repeatedly making this choice day after day after day guarantees that you will never reach your writing dreams and goals. Saying I never had the time is just an excuse. It's a rationalization. The real truth that you chose to allocate your time to other things.
Don't make the wrong choice. Write. And keep at it.