For some reason the term "self-employed" seems to have a sort of mystical power. I'm not even kidding. I speak from experience. People ask me what I do for a living and I tell them I am a violin teacher. The follow up question is usually where I work and I tell them I'm self-employed. That's when I get one of two looks:
Look Option 1: The cynical look. I am clearly full of it and probably make no money because I am a self-employed music teacher. If I was any good at what I do I would be working for a school.
Look Option 2: The enamored look. I am a wild and crazy musician living the dream life of freedom. No rules or conventions could hold ME back.
In reality I am somewhere in between those two. I do make a living off of my self-employed teaching state. I choose not to work in schools because that is a totally different type of teaching that is really not my cup of tea.
I can set my own schedule but being self-employed actually takes quite a bit of work. I have to spend quite a bit of time at the computer responding to emails. I get no healthcare benefits or paid vacations. Plus I have to keep track of every business expense if I want to have any hope of tax rebates.
What this is all leading to is the fact that self-published ebook writers are self-employed individuals. Even if you only make a few cents a year from it, the same rules still apply. Establishing a self-employed business takes time. It's not a get rich quick scheme. At best you can reasonably hope for steady income that allows you to support yourself.
But reaching this point will take years. Any startup business takes 2-5 years to establish. It also takes consistant effort on the part of the owner (that would be you). So if you write one ebook and then don't do anything to promote your business for 6 months, don't expect sales to be the same.
If you are writing as a hobby, that's fine. But you still need to approach it in a professional manner regardless of how much money you make. Acting like a professional, even if it's just online, is crucial. It's ok to appear "like a human." But at the core you still must be a professional. If you want people to treat your work seriously, you must take your craft seriously.