Flat, tired, and unable to care about things you used to care about. Two different situations can produce that, and what helps is different.

It is a Tuesday in the middle of something. You get through the day and answer the messages, and by any external measure you are functioning. And you feel almost nothing about any of it. This is where a lot of people start wondering whether something is wrong, and where they run into a problem: from where you are standing, burnout and depression feel almost identical. Both are flat. Both are tired in a way sleep does not touch. And both take the things you used to want and turn them into admin.
It is not a failure of attention. The overlap is genuine. Exhaustion that rest does not fix. Losing interest in things you used to enjoy. Getting irritable with people who have not done anything. Finding it hard to concentrate on things you used to find easy. A body that has started complaining. All of that shows up in both. Most articles about this hand you a symptom checklist, and the checklists overlap so heavily that you finish them no wiser than you started.

The more useful question is not what it feels like. It is what it does over time, and where it follows you. Burnout is usually tied to a context. It has a shape that matches something in your life, and when that thing genuinely stops, it usually begins to lift, even if slowly, even if incompletely. It tends to be loudest about the specific domain that produced it. The flatness that is not context-bound travels. It comes on the holiday. It sits there on the good weekend and at the wedding you were looking forward to, and it does not much care whether the week was hard. That is the distinction I find most useful, and I want to be careful about how much weight to put on it, because it is a rough guide rather than a test.
The obvious experiment is to take two weeks off and see what happens. It is a reasonable instinct and it is imperfect for two reasons. Two weeks is often not long enough. If you have been depleted for eighteen months, a fortnight gets you to the point where you can feel how tired you are, which frequently feels worse rather than better. And you take yourself on holiday. If what is going on is not about the work, the work being paused does not remove it. People come back from two genuinely restful weeks and are dismayed to find themselves exactly as flat, and conclude something is deeply wrong with them. Often what they have found is just information.
Because different things help, and the wrong help is discouraging. If it is tied to a context, then the work is largely about that context and your relationship to it: what you are carrying, what you have agreed to, what you are afraid would happen if you stopped carrying it. Rest is part of that and rarely all of it, since most people who burn out do so for reasons that survive a holiday. If it is not tied to a context, rest will not resolve it, and continuing to prescribe yourself rest tends to produce a particular kind of despair, because the treatment keeps not working and you start to think the problem is you.
They are not exclusive. A long stretch of the first can become the second. People arrive with a tidy story about work and, three months in, we find something considerably older underneath it that the work was doing a good job of covering. And this distinction is a clinical judgement, made over time, with a person, not a thing you settle from an article. I have written it as clearly as I can, and I would still not want you deciding which one you have on the strength of it.
Not at a threshold. There is not one. If it has been going on for a while, if the people close to you have started to notice, if you have stopped being able to tell whether you are tired or something else, that is enough of a reason. And if it is heavier than that, if you are having thoughts of harming yourself, please do not wait for a therapist's calendar. Tele-MANAS is free, staffed around the clock, on 14416.
Written by Satlaj Sachan, a counsellor in Bengaluru working Book a first conversation.