It was the interruptiong of your focus. This tends to happen to people starting out with energy work, then someone who is good at it, because of the skill that develops, like driving a car or riding a bicycle. When you are first doing it, it requires your constant attention and focus, and if some of that attention slips, you might find yourself wiping out pretty bad. Later, when you practiced and worked alot more, if you become distracted, you will be okay, because alot of it is now become second nature. You will probably not wipe out, unless something blind sides you. Your brother caught the fall out as well, since he was in the room. This is easy to recover from.
Doing it from a visualization practice, just pull the excess energy out of you, and smooth your personal energy back out again. Do the same to your brother. If you don't want to do it to him, you can wait while he is asleep or work it at a distance, just visualize him there in front of you, and will things back to balanced, more easily to live with state. If you need something more to help, do it over something that would have something of his person in it, like dirty laundry, or his bed (when the sheets haven't been cleaned) or something.