Sorrow can be alleviated by good sleep, a bath and a glass of wine. — St Thomas Aquinas.

TMH — I’m not sure why you feel your ministry has been worthless if the Catholic faith is true. I want to reassure you though, as I’m sure your wife has done; I for one am certain that you have had a tremendously positive influence on many people, bringing them closer to Jesus. You may not have done so by teaching them the Catholic faith, but if the Catholic faith (in theory) is perfection then your teaching (and that of all Christians) is good. And the perfect must not be thought to be the enemy of the good.

There’s probably not much I can say beyond that, that you haven’t heard a million times from the books you’ve read; except that I’m sorry, and I will pray for you.