Its the second part. I would never actually harm anyone.
I figured. That kind of guilt trip is exceedingly common in christianity. It's part of the way christianity tries to exert social and psychological control over you. If it can get you feeling guilty for merely existing, in your "sinfulness," then you can become convinced of a need to seek "redemption" in their approved ways.
You don't need redemption. You never, ever did. There's nothing wrong with you being who you are.
You already recognize the difference between your actions harming someone else, and you simply... being.
got me to commit a sin in my mind.
There again I have to ask: what "sin?" A great many of the things christianity considers "sin" are not harmful, to you or anyone else, and christianity uses them to, once again, exert social and psychological control over you, so you won't leave - so you feel like you can't leave, since (to use one example) blasphemy is such an egregious "sin."
No it's not. I am, and remain personally convinced that the christian god is not a morally praiseworthy being. If he or it existed, it would be morally obligatory to oppose it, in every possible way. See? I just committed the "sin" of blasphemy. I know that's a mortal sin, according to catholicism.
So, mortal "sin," right? It just fit all of the qualifications. According to catholicism, if I don't repent of that sin, appropriately, by receiving confession from a qualified priest, and I don't make a sincere act of contrition, I'm headed straight to hell, no purgatory, no intermediate grace (probably), the minute I'm dead... right?
Except that I don't care what catholicism or christianity in general considers "sin." Not even a bit. Sin is their game. They play it on their terms, in their churches and congregations, and they use it to manipulate and abuse their adherents.
Now then: if you do something that causes harm, I think you have a moral responsibility to try to correct that harm, and at the very least, not to continue doing it, once you understand the harm you're causing.
But that has nothing to do with sin, or hell (or heaven), or an afterlife. It's about us making a life with each other in the here and now. Our relationships, our communities, and our societies work better when we try to help, where we can, and we try to not to harm, where we can avoid it.
That's reason enough to avoid causing harm, and to try to make amends when you do.
At the end of the day, Catholicism hurt me a lot.
I don't doubt it.
So, IMO, start to see "sin" for what it is: a mechanism of control. It's not about moral behavior. It never, ever was.