I didn't answer. He was right. How long can a man stay awake? I hadn't dared to shut my eyes in maybe seventy-two hours. Very soon now I'd doze off, and the instant that happened they'd jump on the little water that was left. 

这句中 very soon now 的 now 还是副词“现在”的意思吗? 译文是我现在很快要打盹了。