Burnout is defined as physical and emotional exhaustion from chronic stress. Dealing with burnout or being overwhelmed are both consequences of high amounts of stress. With overwhelm, you might be experiencing stress for a long time, which leads you to becoming overwhelmed with everything you are thinking and dealing with at the same time.
Burnout is similar, though it is typically when you become so exhausted mentally and physically, then it can affect your work, motivation, and energy. But remember it is not things themselves but our perceptions that cause this to happen. By finding balance through experiencing hardship rather than suffering we can cope with burnout.
Meditations 2.17 staes "Of human life the time is a point, and the substance is in a flux, and the perception dull, and the composition of the whole body subject to putrefaction, and the soul a whirl, and fortune hard to divine, and fame a thing devoid of judgement. And, to say all in a word, everything which belongs to the body is a stream, and what belongs to the soul is a dream and vapour, and life is a warfare and a stranger's sojourn, and after-fame is oblivion. What then is that which is able to conduct a man? One thing and only one, philosophy. But this consists in keeping the soul within a man free from violence and unharmed, superior to pains and pleasures, doing nothing without purpose, nor yet falsely and with hypocrisy, not feeling the need of another man's doing or not doing anything; and besides, accepting all that happens, and all that is allotted, as coming from thence, wherever it is, from whence he himself came; and, finally, waiting for death with a cheerful mind, as being nothing else than a dissolution of the elements of which every living being is compounded. But if there is no harm to the elements themselves in each continually changing into another, why should a man have any apprehension about the change and dissolution of all the elements? For it is according to nature, and nothing is evil which is according to nature."