CC,
Now that you have a priest to consult, I hope that you will ask him the questions that you have asked us here. I am sure that he will review with you the conditions that make a sin mortal.
Here is the question from the Baltimore catechism on mortal sin:
What three things are necessary to make a sin mortal?
To make a sin mortal these three things are needed:
1.the thought, desire, word, action, or omission must be seriously wrong or considered seriously wrong;
2.the sinner, must be mindful of the serious wrong;
3.the sinner must fully consent to it.