The "aggressive energy" treatment is one of the initial protocols followed within five element style acupuncture. It is described within our classical acupuncture section within the "Initial Treatment Section".
To begin to answer spunkycats question I would like to know how many treatments you had and how long you have been experiencing these symptoms (and what is your original complaint - i.e. are they related). Side effects from acupuncture are very rare and they only arise from completely incorrect or over treatment - even then symptoms such as fatigue, breathlessness, etc. usually last only a few hours to a day or so at the most.
Within five element acupuncture theory, which I do not fully subscribe to - nor am I a practitioner of, the aggressive energy treatments intend to draw out very deep imbalances in a person and strong reactions (with any variety of symptoms) are theoretically possible. I have seen some very interesting responses from five element treatments - particularly the aggressive energy treatments, but I'm never quite sure what it meant. Unfortunately, I wasn't able to follow up with patients who had these types of responses to see whether the reaction correlated with any positive outcome in the long run.
You should discuss these reactions with your practitioner and if you are uncomfortable with their answers and/or you are not improving at least in some measureable way within 3-7 treatments, try a different practitioner of a different style and see what kind of results you get.