And how can you tell?

The key to figuring out which of the above you have starts with knowing how much you cost to run. You, personally.
Too many self employed people blur the lines between their business and personal outgoings, leaving it up to an accountant at year end to detangle the mess. While annoying your accountant is indeed a noble and worthy cause, in this case it actually does not serve you in your quest for financial peace of mind.

Here is what you need to do:

Start with the budget planner on this website, It’s your money . This website is true to its name, it was created by the Financial Regulator, so it is in fact, your tax euros that are paying for the site. Use it!

If you really can’t deal with it for whatever reason, then make an appointment with MABS. They are a free Money and Advice and Budgeting Service. You do not have to wait until you are in dire straits before calling to them. In fact can you see why they would prefer people to go to them BEFORE they hit skid row?

So doing out your home budget tells what you need to have in your sweaty palm once everyone else has had their cut.  Now have a look at your business. Does your profit less tax meet your home budget requirement?

No - you have a hobby
Yes, just about - you have a job disguised as a business
Yes, and there is plenty left over - congratulations, you have a business!

Ideally, you want to get to a stage where your business is generating enough income for you to draw a salary and a build up a hefty pension without you actually working in the business.