At 3% you only have the fat surrounding your organs and spinal cord left.
I found these posts on a Anabolic Fitness post - How low is too low with bodyfat
"You need bodyfat for a lot of necessary things - cushioning your heart, providing a reservoir of raw materials for synthesizing hormones, all kinds of stuff. Your body is bound to start cannibalizing lean mass pretty soon, in order to protect the precious resource of the little remaining bodyfat you have" - bjaarki
Here's what will happen eventually. The soles of your feet, especially the balls, will start to ache first. Then you will notice bruises starting to appear in the strangest places, without any memory of trauma. You may get a nosebleed or two. Your strength will, amazingly, stay high, especially if you are on gear, but your endurance will suffer. However, it won't be in the traditional sense. You'll just suddenly get lightheaded and shaky in a workout. If you're on a winny cycle, you may see spots after a workout, and your pupils will constrict spontaneously at times of physical stress. Your mouth will always be dry. Oh yeah...your friends will ask you what the hell you are doing to yourself. I can tell you that for me, 4% is the absolute lowest I can stay upright at. Maybe I could get lower..who knows? But what looks different from 5% to 4% anyway? Your face, really, is the only thing that looks any different there, and it is because your eyes will sink in and your neck will look gristly - fukkenshredded
I'd say you would def want to start raising your body-fat back up to 5 at least. Like the above says, you wont notice much difference between 3-5, except your face will look better.