וּבְדַבְּר֣וֹ עִמִּ֔י נִרְדַּ֥מְתִּי עַל־פָּנַ֖י אָ֑רְצָה וַיִּ֨גַּע־בִּ֔י וַיַּֽעֲמִידֵ֖נִי עַל־עָמְדִֽי׃
At habang siya'y nakikipag-usap sa akin, nahulog ako sa mahimbing na pagkakatulog habang nakasubsob ang aking mukha sa lupa; ngunit hinipo niya ako at itinayo niya ako sa aking kinatatayuan.
Radak
ותרדמה נפלה על אברם, this exhaustion was due to the marshalling of all of Avram’s spiritual resources to receive these prophetic visions. We have evidence of these reactions in Daniel 8,18 who describes these physically debilitating reactions when he involuntarily went to sleep on the very ground on which he had been standing. (he did not have time to lie down on a bed) He had to be revived by the angel. He referred to such weakness also in verse 17 of that same chapter. Avram, at least at the beginning of his prophetic vision, did not experience such a weakness. The reason was that at the beginning of the visions G’d showed him there were only positive developments. Now when G’d showed him the downside, he was overcome with the impact of what G’d showed him.