I understand your frustration with growing up and thinking you have been told the truth about what the Church teaches and now finding that maybe you weren’t, or that there is something you weren’t told. You are left not knowing for sure what to think, I imagine, nor how to fix your pickle of trying to figure out exactly what is right.
The voice of truth is hard to discern when there are many voices. Most people on this site (or in your parish, etc.) are telling you the truth as they understand it, and as they have the capacity to explain it.

I doubt people are trying to get it wrong for you. What helped me was finally hearing a Catholic voice that I recognized as true and faithful. Then, once I had a large, solid sample, I could pick it out from the crowd again, and at that point I realized the message *was *consistent. For me, it was reading what some Doctors of the Church wrote. It was St. Teresa of Ávila and St John of the Cross. Both wrote about, oh, 500 years ago. I could see how a well centered Catholic viewed things after reading them.
That’s why so many recommend the Catechism to you, because they are confident its voice won’t lead you wrong. But as you point out, if you don’t know how to piece it together, it can seem contradictory. (I mean about how you mention you are reading in the CCC about conscience). If you truly know that to do a particular thing is against God’s law (ie your real conscience tells you it is wrong to do), then do not do that thing. This is indeed so. Your own mind would condemn you for doing it.
Just to be sure there is no confusion in the peanut gallery, yes, the real conscience could be ignorant of the truth, but if it is truly ignorant, the person will not realize this. And, what I said is unlikely to apply to masturbation, for example, because typically people don’t find themselves believing in their heart that this evening it would be against God’s law for them to fail to masturbate.
By the way, you are Catholic.

The Church is infallible, but only in set circumstances, which are detailed in the CCC. The column written by your bishop in the local diocesan paper is not infallible, for example, not in itself. He might write about topics that are infallibly taught, though. It is possible to commit a mortal sin in thought, without getting to a deed. Probably, though, it was not mortal of you to hesitate that day about going to mass. You would have some inkling if it were, and you don’t have an inkling. If it bothers you, do go to confession and mention it anyway. That way you will get rid of it from bothering you.
You can love God and try to be a good person! Truly love God, and humbly accept how he wants to direct your life. Take up your cross daily and follow Jesus, denying yourself. This method does work! I can honestly tell you that for me this dovetails beautifully with living a Catholic life. Living a Catholic life only seems to help me on this path. Pray to the Holy Spirit to show you the way. I think you are doing that anyway, of course, but it never hurts to suggest it.
Praying for you
Pug
P.S. I was very busy today, and this thread filled up with posts while I was busy, so if I missed something, I apologize. I didn’t get every one read very well. How cool that you got married in the Vatican!