Form 1099-NEC, sporadic activity?

I perform basic housekeeping (literally cleaning the premises) duties at a non-profit organization (a relative of mine is an employee of the organization) and I got a 1099-NEC.  This is my only income. I do not have a "cleaning business." While I can perform these duties after hours during the week, I normally perform these duties on a Saturday or Sunday, when they are closed, but not every Saturday or Sunday as I can choose to skip a weekend here or there and essentially perform these duties on my own schedule. Can this be considered a sporadic activity, which presumably permits one to not pay self-employment tax or must I report it as self-employment income, as if I run a business?