I'm flinging random thoughts at you, and I apologize in advance. I think the AHE AAP Yaoi is a "McGuffin" in all this. It is not worth your time sorting out at the moment. It is just where your mind wandered, and even though it is your mind, you did not wander there alone nor unprompted even though I do not want to speculate why it wandered there. The fact that it did not wander there alone makes it not a "psych" thing and not an "anthro" thing, but a "soc" thing.

I feel horrible for kids and young adults today because every bad idea is encouraged, every thing that pops into one's imagination is treated as if it means something real, and the time when a person is asking questions about literally everything possible is treated like the time their "real" self and their real personality is asserting itself. And on top of that their minds are saturated in porn and lies from every special interest (drug company, all major governments, etc) and their parents are generally distracted or working too much to notice, and the network of adults that were there for previous generations are just not there and instead teachers and homework are all there is (besides the internet).

The daydreaming you did is just that: day dreaming. It means nothing and reflects nothing about you other than that is what you were wondering about. There could be any number of reasons for it, but from what I gather that kind of daydreaming is not uncommon and there is a whole subgenre of art or anime that indulges it. It also reflects more about the world you are in than it does about you, the same way heavy metal in the 70s and 80s reflected the fear of a civilization ending nuclear war than it reflected kids naturally predisposed to doom and gloom. Once that started to disappear, "metal" became hair bands reflecting good old teenage raging hormones again.

The bad sex you had also is nothing new and I can't imagine a solution. Guys are seeing the most insane sex acts done by literal professionals who are acting and acting "pleased" at real pain and acting pleased during acts that take a woman's body a lot of practice to get used to (before "enjoying" it can be considered, and it usually isn't depending on the act). Young women seeing that as "sex" have every right to find some other way for their minds to wander.

I recommend reading and practicing Stoic philosophy, or reading Zen or Taoism. I find them very related anyway if you get deep enough into them. Plato and Aristotle are also great to read. You are not your thoughts and you are not what happens to you. The worst thing, and I do not think you any where near this, is when people allow themselves to be replaced by: their thoughts, their impulses, the things that happen to them, and the things others tell them. This is not a new thing and Hannah Arednt discussed how in Nazi Germany many people, perhaps more those who blindly climbed the bureaucracy, had their thinking reduced to "sloganeering" where they had no real thoughts and no real critical thinking because some slogan was made readily available for them to repeat instead of thinking.

Step back, build your own self and your own mind and your own body, as there is no 'mind' separate from the body (no "identity" so many talk about even when they are talking real aspects of themselves), and just for a while question EVERYTHING anew. Everything! Every time you open a door, stop and ask yourself if you know what is behind it. Are you ready for what is there? If you are right, and you see what you expected, don't celebrate. Add it to your body of knowledge. When ever you see some claim made, save it and see if it comes true. Don't celebrate it, don't lament it. Just keep track. Step back from what you do not know and grow to rely on what you can verify yourself. It will be very little. You will not be able to join in a lot of conversations, especially on line. Even if you find a source, does that verify the claim? No, not really. Be less firm about what you yourself can not physically touch and affirm.

There is this idea, and the term for the idea is "the passions", but it is not the current way we see our "passions". It is not what we are "passionate" about. Instead, it refers to the ideas and feelings and compulsions that come over us passively. I see an attractive woman and my eyes and my mind wanders. Nothing actively did that, it is a thing that distracted me passively. She is not a "thing", the thing is the attention in my mind that "it" got using her as a symbol or something. If I only see her, then that's it and I move on. But some imagine and imaginary version of something, not really her at all, distracts me if I let it. Similarly let's say we're in high school and we have a test tomorrow. Our fears about the test are passions that distract us. We are projecting onto the test a set of events that are not happening and probably will not happen. But if we keep being distracted then we are not preparing. We might be creating self-fulfilling prophecies. Stoicism both on its own and as it was continued to be written about in the same part of the world by Orthodox Christian monks, addresses how to separate ourselves from these the same way Zen does.

A similar set of things, though graduated from inner thoughts and into dynamic social situations, are described by Transactional Analysis and in the tiny book that sets "TA" out very clearly, Games People Play" by Dr. Eric Berne. I is a great read. Though the kinds of sexist imagery used in the 1950s might put some people off, the points he makes and the truths the book contains are not cheapened by the way he conveys them using the cultural tropes of his era.

This questions have been wrestled with for as long as we've been able to think. Many religions and mythologies have been written to make sense of it all, and they seem to all be written at specific junctures in time. Chinese philosophy reflects the political changes in their world. The most amazing things about centering ourselves were written during times of utter chaos and war. The various writings in the eastern Mediterranean written as a result of the interaction of the Hellenistic, Jewish, Roman, North African, Anatolian, and even Indian cultures, show many people working out big ideas and big struggles of individuals in the transition from the Roman republic to the Roman empire. While you can't avoid religious ideas in these writings, you shouldn't want to. You have to (if you choose to get into them) see their use of the word "God" as meaning something very different than what most people use it for today. Similarly "wisdom" books from various traditions, be it the Havermal or the Jewish book literally called "book of wisdom" in the catholic bible or any other, point to similar things that Stoics point to.