It is entirely possible in an apocalyptic scenario that you might wind up alone for an undetermined period of time. Isolation may be difficult, even if you are in a relatively safe position otherwise because of our innate social animal psychology. At the same time, it is not like solitary confinement, as you are free to go about and continue your daily tasks.

How would you deal with it ? How long do you think you could do it for before biting the big bazooka ?

I believe man's nature is one of relationships and habits, and that it is possible to temporarily focus more on good habits if there is a lack of relationships. Likewise, a focus on strong relationships helps weather stormy times where habits go out the window.

And so I have to think that one must take inspiration from hermits, monastic life, stoicism and the like

You must be able to find respite in hard labor, you must get a routine that fills your days and your head. You must project your needs for happiness onto your environment and make IT better and safer because it is easier to keep your spirits up in a good place. You must remember and truly believe that your good will and your good habits can carry you as far as you keep them.

But it's only pushing the inevitable back. How long could you guys last ? Weeks ? Months ? Years ?