Viability is arithmetic. Does the gross margin work, meaning is the thing you sell worth selling after the direct cost of delivering it. Do customers return or refer. Does acquiring a customer cost less than they produce. And is there enough demand at your price for the volume you need. Four questions, all answerable from records you have, and none of them concerned with how the year felt.
If those answers are sound and the year was hard, you have an operations problem rather than a business problem. Those are fixable: pricing, delegation, better process, declining the wrong work. It is worth being precise about that distinction, because operations problems feel exactly like failure while you are inside them.
If the answers are not sound, the useful question is whether they can become sound with a change you can actually make. Different customer, different price, narrower service, lower cost of delivery. Some businesses are one adjustment from working. Others require conditions that do not exist, and continuing costs money and years that could go somewhere better.
The question about whether you want to continue deserves the same honesty and is not the same test. A viable business you have come to dislike is a real situation, and running it badly out of obligation serves nobody. Selling, changing what it does, or closing deliberately are all legitimate outcomes.
Set a decision date rather than deciding continuously, because continuous evaluation is exhausting and produces worse answers than a considered review. Name what would have to be true by a specific date, write it down, and hold the question until then. Deciding in a bad week is how viable businesses get abandoned, and deciding never is how unviable ones consume everything.
Take the assessment to somebody outside the business before acting on it. Not for permission, but because a year inside a business makes it genuinely difficult to judge your own numbers, and an accountant or an experienced owner will read the same figures differently. This is the situation where an outside view is worth most, and where people are least likely to seek one.
If you decide to stop, do it deliberately rather than by attrition. Finish outstanding work, tell customers, collect what is owed, close accounts properly, and keep the records. A business wound down cleanly leaves a reputation and relationships intact, both of which matter for whatever comes next. One that simply stops responding costs considerably more than the closure itself.