What does this quotation mean? "I tried to take a breath and couldn’t. The moment felt surreal—no, not surreal, absurd."

In chapter 22, Amir comes face to face with Assef, who he does not initially recognize. When Amir asks for Sohrab, the little boy walks out from a back room, and Assef begins rubbing his stomach in a sexual manner that suggests Sohrab is his a sex slave. When Assef asks Amir, "Whatever happened to old Babalu, anyway?", Amir feels the blood immediately drain from his body as he recognizes for the first time that he is standing face-to-face with the evil Assef (Hosseini, 241). Assef then reminds Amir that he never forgets a face and is not fooled by his fake beard. Amir then mentions that he cannot breathe or wink because he is stunned at the fact he is staring at his childhood tormentor and the person who raped Hassan. Amir also mentions,

The moment felt surreal—no, not surreal, absurd—it had knocked the breath out of me, brought the world around me to a standstill (Hosseini, 241).

Amir is commenting on the unreal, bizarre coincidence that Assef, the person responsible for ruining his childhood, is the same person currently molesting Sohrab. In a strange twist of fate, Amir must defeat his childhood nemesis and save Sohrab in order to find redemption.