perhaps, that was my thought as well.
yet after further readings and thought, i dont think its that simple. its related to the reucrrence, yes, but its the way in which he understands it.
the most abysmal thought seems to have to do with the meaning, or impact, or a full significance of the eternal recurrence. it “divides” Zarathusrtra into two, and i remember him mentioning how language covers up or distorts the true meaning of the recurrence, the “circle”. his animals dont get it, of course, but due to language they THINK that they do.
there is some WAY in which the recurrence is grasped, some deep nature, some ultimate significance or relevance or conclusion, which causes Zarathustra such dismay, which causes him to jump up and scream, then to lie down for 7 days and be unable to speak. the “horror” of the thought. i agree it is the eternal recurrence, but just saying thats what it “is” doesnt do justice to HOW its understood, and what exactly it means. the abysmal thought itself and our understanding or idea of “the eternal recurrence” are two completely different things.
for example, by what he says it also seems as if the “great disgust with man” is the “monster” that “chokes” him. we need to understand how this disgust manifests and what it means, particularly in light of Zarathustra’s benevolent character. when we put together the eternal recurrence and this “great disgust” perhaps we get the answer: that the eternal recurrence and existence of the reasons for this great disgust, whatever it is that Zarathustra most hates or reviles, will always be-- that this horrible thing, sum or result, will never go away, never stop existing.
yet, the abysmal thought must be higher than this, as well. it must reconcile this eternal existence of the reasons for Zarathustra’s disgust with the circle itself, and with all other perspectives. and we cant forget that Zarathustra is “redeemed” by his abysmal thought, no matter how horrifying it is. so it seems inconclusive to just say that he realises the eternal recurrence and existence of all this disgust and horror, he must move BEYOND this realization as well.
perhaps by reaffirming the opposite, the recurrence of the overman, as well. but then again, why stop there? it seems too shallow a stopping place for a mind such as Zarathustra’s, particularly since we know he can grasp this meaning completely, and we are without reason to see why it causes him such distress and physical agony.