It sounds to me like you were indeed releasing excess energy, a natural process also manifested (at different levels) as laughing, yawning, sighing, muscle twitches, heat coming off, and more. "Laughing like a lunatic" can continue for half an hour or more as a release of some particular "charge" and can be found to be quite cathartic (in a normal person) as long as it occurs naturally and is not forced.