Welcome to the community virtualmark. Great first post and sounds like the door opened for you a bit
It is strange, these experiences on DMT. All trips are only able to be interpreted by the experiencer, however I'll share my two cents for whatever that's worth to you.
The forgetting / remembering I've experienced many, many times and it's commonly reported here. With more 'practice' (although I hate using that term), it becomes easier to bring back more and more of the experience with you into your waking reality. Personally for me this took a few deep trips of absolute craziness before any sort of real understanding managed to come back with me, there tends to be an integration period between journeys for me that sometimes last months before I feel I'm ready to go deeper. The benefit is, just like you experienced, going 'back there' is almost always like picking up where you left off, like you never left the place to begin with and this makes it easier with repeated visits to get a general understanding of what's going on.
The terror thing I can relate to greatly. Terence McKenna, one of the greatest pioneers of psychedelics, had tripped more times than he could probably count but still maintained the fact that a certain dread came over him every time he was about to dose. He said it's the sheer terror of taking the substance that's proof to the power of the experience, and I agree with him on this since it's not something to be taken lightly. Nowadays I think, for myself, I understand this dread more. I honestly feel it is my human ego that causes this fear. The fear of transcending the human experience is a terrifying concept to my mammalian brain that has been programmed to fight for it's survival. The animal brain's command to survive comes into conflict with the psychedelic experience which wants you to take flight from your body and travel deep into unknown territory. My own ego will stop at nothing, even begging (I've had an experience of seeing my ego from the outside/inside while this is happening) to keep me in orbit around planet earth. However, this is a paper dragon as it were, the terror is a thing to be overcome and there isn't any real or inherent danger. You will come back to reality even if your ego tries to convince you otherwise.
It's interesting you use the moniker SWIM when discussing how, while observing yourself breathing, it was almost like it wasn't you (or, truly a SWIM - Someone Who Isn't Me). I'm not sure who first came up with that term, if they meant it as a way to report experiences without incriminating one's self or if they actually meant the SWIM that seems to come out on deep journeys. Regardless, I love the term because of how accurate it describes the one who trips. 'I' in my ego sense of the term, never leave planet earth. The ego lives and dies in this realm, however BIG I, or SWIM, DOES live on outside of the earth life system and it's this strange relationship of small me and BIG ME being one and the same, yet seperate, that is one of the greatest mysteries of the psychedelic world to me.
Aliens and entities don't always show up, I think they do when they're sure you can handle them in one way or another and if you're just starting your journeys there is a possibility that they are allowing you to get your feet wet before they think you're ready for them. This is only my opinion however I have nothing but personal expereinces with them to go on and in my first breakthrough I actually did meet an entity so I'm probably not the best one to talk about when and why they show up.
All in all, what I get out of the psychedelic experience is as follows, and these are knowns to me however a known to me might only be a belief or theory to others, but in case you wanted my input this is what I know for myself:
1. There is a Non-Physical Reality (NPR) that members of this community call hyperspace
2. The 'entrance' to hyperspace is within our own minds meaning we are all connected to it at any given moment in time, whether aware of it or not
3. Hyperspace is an impossibly large, perhaps infinate area which is navigable to some degree and seems to exist outside of the flow of time
4. Apparent discarnate entities reside in this place and communicate with a form of instant download, telepathy, or Non-Verbal Communication (NVC)
5. Human experience has been revealed to me to be an experiment with seperation (for whatever reason) and the only way to be able to do this is to make the experiencer forget he is a part of the whole.
6. Psychedelics are 'easter eggs' hidden in the 'game world' of Earth to remind the human that he is actually not human but a part of something much larger, much grander, and in the truest sense, he/she/it can never REALLY be seperated from the whole in anything other than perception.
Many might not feel the same way, but like I said these are my personal knowns and I share them with you just for the sake of helping make sense of your own journey.
Happy travels friend
All posts are from the fictional perspective of The Legendary Tek: the formless, hyperspace exploring apprentice to the mushroom god Teo. Tek, the lord of Eureeka's Castle, is the chosen one who has surfed the rainbow wave and who resides underneath the matter dome. All posts are fictitious in nature and are meant for entertainment purposes only.