Voluntarily quitting a job seems to involve running the same predictable gauntlet of emotions as a 19-year-old the first time he drinks alcohol. (And, yes, I know the legal drinking age in the US is 21, and we all remember how we felt when we first tried our hands at serious drinking at 19-ish - your mileage may vary.)
Those emotions involve guilt, introspection, anxiety, regret, hope, and a guilty sense of freedom that leads to the feeling that perhaps we should really stick with that initial, gut reaction of just feeing guilty all around.
It helps in these cases to have an exceptional spouse, family, and other emotional safety nets.
it also helps, as my own exceptional spouse has pointed out, that none of this has any meaning if I fail to believe in myself. I was a competent, experienced individual before I quit my job. Nothing has changed since then. It is entirely between me and my own inner demons to put aside our differences and acknowledge that I am just as capable as I was two weeks ago, let alone twelve years.