You'd be amazed at how much you can take, and still be OK... even be great...
One minute you think "If one more thing falls on my head, that's it, I'm done". Then it does and... you're not.
You're still strong enough, and there's still hope, and things will still get better...
Because the alternative is... what?
Giving up?
Never.
Failing? Not an option.
Dying? Not a chance in hell...
Enduring, until you change "making it" into "winning it"...
That's what you do.