the feeling of being near to fainting but it not quite happening is so awful imo. it's happened to me three times, all while i had to stand at parade rest or attention any longer than 10 minutes. i bend my knees and everything but it still happens.
but it's like, i start to feel really clammy and my chest starts hurting, which is followed by awful dizziness and my vision starting get get fuzzy. shifting around, wriggling my toes, and taking deep breaths doesn't help me at all. i'm just like "wel hopefully this doesn't last too much longer" and tough it out the best i can. my uniform pants are p tight so i'm thinking it might be from that but i dunno.
i can recover pretty quickly from it, though. when it happened during a practice inspection, they sat me down and got me some water and i was on my feet again in about a minute.