You can't. Because it's impossible to describe how hard it was for me in words, you would have to experience it yourself.
When I say "burnout", I don't just mean mental burnout. I've even been in situations where I went completely broke, lived homeless, and much more sensitive details I can't talk about on a public forum.
Of course it doesn't have to be all life threatening to qualify as a "burnout". I've been through more moderate burnouts where I just couldn't keep up mentally. I started doubting humanity (I still haven't fully recovered from this and don't think I ever will).
But overall, these are things you can't just describe. Even if I did, people who've never been through one will never understand.