Have you ever done acid? The things you describe are things that I experience either during an acid or MDMA trip (yes, rolling is trip-like)... although not the déjà vu part. I've had déjà vu before, yes, but relating it to the other things you do is a personal experience that I haven't yet shared with you.
The way I look at the sub-conscious these days is that it's a "lighter" you. It's not that you have a density in the same sense that matter has a density at an instant in time. No, what I mean is that your subconsciousness is more related to the essence of you that transcends moments/instants. It's the you that materializes like a rain droplet condenses from the cloud that it transports itself in. Every single human being has a unique life and therefore unique experiences. Yes, yes, we're all subjective... we don't even agree if we're all subjective for Heaven's sakes. But your unique experience is based on a certain principle of you that is interconnected with other principles that you might say you're related to. For example, when you talk about yourself and you say, "I'm pretty much a geek", well, you're identifying a parallel profile (geek) to your profile (you).
People often say that the body is a vessel of the spirit in such-and-such earthly realm or whatever. Well, a word is the same for the spirit of that word, or the principle of that word. Now, words are parallel to ideas by principle. Somewhere, in time and space, these ideas converge and manifest as one and the same. This sameness is an aspect, just like the varying proportions of difference that cloud the Oneness a lot of spiritual members on here refer to. Saying "Everything is one" is pretty vague. I mean, yes, you used the right words, but the right words don't necessarily parallel the right idea. If you recall, I made a thread awhile ago about whether the verb "to be" is active or passive. Well, to be is such a vague word that by talking about it we could pretty quickly reveal notions of ideas as shared by English speakers and also how they diverge. I daresay it is the vaguest phrase (word) in the English language and thus the closest to the "truth".
Point: we all have separate experience. When we connect ideas, we have no idea of how alone we are.
The word "mania" has "man" in it. Just saying.
EDIT: It's like, I can tell you we're connected and I call tell you we're separate. I can tell you both and you'll understand both. But if I tell you both of them together, what are you going to think? Personal experience. Your separation...