I can only imagine! I’m not a competitor but have gotten down to probably just under 9-10% quite a long time ago. I was definitely at very low energy and just felt like crap. I like to maintain somewhere between 10-13%. When I hit close to 10%, abs are clearly visible and defined, which is basically my ideal body comp, though as most here are, am always shooting to gain more size/strength.
Stay the course and good luck!