don’t worry, it’s not mortal,
if you had realized what you were doing and kept doing it, then it would be mortal,
but you resisted and overcame, it was a temptation, and temptations are not bad,
they in fact can be good, because by resisting temptations we become stronger
against them,
you can actually mention the things you struggle most with in confession, even if
you don’t commit them, you can just tell the priest, like in your case for example,
“i have been tempted to impure thoughts” and by that you will receive special graces
for better resisting and overcoming those temptations, and possibly not be so
strongly tempted to it,
but i’d like to point out, even if you commit a sin, don’t let that stress you out,
of course we should have sorrow for our sins and truly wish to amend our lives,
but Jesus does not want you to worry or stress even over your sins, you simply
need to pray and trust that God will help you overcome them, and work diligently
and constantly in resisting them,
it is only when we do not ask for help from God that we fall, we get our strength
entirely from Him, and when we think we can do it on our own and not ask for
His help, that is a great insult to Him, and it is one of the biggest reasons why
we fall,
another big reason why we fall, is because we are to attached to the things and
comforts and creatures of this world, even our own selves,
we must detach from all things, and die to ourselves, in order to be filled completely
with God.
i’d like to recommend a book for you to read(if you don’t already have it.)
it’s both online to read, and available on tanbooks for a cheap price -
tanbooks.com/index.php/page/shop:flypage/product_id/147/keywords/imitation+christ/
2heartsnetwork.org/Imitation-of-Christ.pdf
i think that will help you alot.
ok hope this helps, tc.