Having had the occasion at times to respond to questions from those who struggle with with scruples I will note here a few things in general one can find in theological works on such:
One must distinguish between a
scrupulous conscience and a
delicate conscience.
A ‘tender conscience or delicate conscience’ sees the finer distinctions and seeks very much to avoid even very small sins …and …who can judge normally between mortal and venial sin…when in doubt is able to make judgments overcoming his doubt by prudence or abide by good advice etc
as for scruples…or scrupulosity
Scruples or those who are even of a higher degree of scrupulosity take venial sin to be mortal…or non sins to be sins…or are plagued by doubts…unreasonable fears/anxieties about sins…seeing them or fearing them where they need not…etc etc
The french call it the doubting disease (though it is not a disease) for one has lot of problems knowing one knows…thus with “doubt” (or more often rather “apparent doubt”)
Of course there are degrees and it is possible for a person to have generally a delicate conscience or a normal conscience and still have a struggle with scruples in certain areas…or to have very* transient scruples* at the time of their conversion …
and a person may go from one to the other…
one combats scruples with a good
regular confessor…
by forming ones conscience…(with such as the Catechism etc)
and with the confessors guidance acting against ones scruples…
possibly by general principles given often historically by confessors to deal with scruples
by prayer…
by trust and joy in living the Christian life…(not necessarily “emotional” by the way)
With the help of your confessor:
Contra scruplos agendum est, et fixo operis pede certandum
(Act contrary to scruples and with a firm foot overcome them)
Overcoming ones scruples…ones fears with a “firm foot”. Learning to act against them under the guidance of your confessor. Dismiss them. Not argue with them. (for example the regular confessor says…“unless you are certain you have committed a mortal sin…go to communion”…and you feel the fear and the doubts and the worries at the time of communion “but perhaps I committed one…?” you tell yourself “I am not certain of any mortal sins and my confessor told me to go” and you act against your fears and go to Communion! or ones confessor says regarding old past sins “only confess old sins if you are certain it was a mortal sin and certain you have not confessed it…(such is often the advice for those who are scrupulous)” one does just that -and if one is mistaken here one it not on you for a it can be the case that those who are scrupulous are in a “different boat” that others.) etc
(now of course if ones confessor tells a person who is scrupulous that something that is manifestly sinful is ok --like it is ok to use contraception or it is ok to murder my secretary …well then one does not do such …one needs then a new confessor to say the least…but that is not likely going to happen…unless his secretary is realllll annoying

…)
(in a way one needs be “scrupulous” about attending to ones scruples…)
When scruples arise --turn to God and let the pass by.
Scruples are to be treated like a barking dog or a hissing goose…one does not stop to argue with a barking dog or a hissing goose does one? (image borrowed from a 15th cent. Carthusian).
They are to be “despised”…“dismissed”…
And again a* regular confessor *is very important here…in even coming to know what ones scruples are…and then what to dismiss… It is he who can particularly guide a person with these difficulties.