I love chlorella but I remember reading about certain people being unable to tolerate it...I took this from the Mercola.com site for you. This may help you determine if this is temporary or if you may indeed be sensitive to it.

"When your body detoxifies impurities you may experience a period of discomfort as these impurities are "flushed" from your system. Because chlorella is such a powerful detoxifier, I urge you to begin your chlorella regime gradually over the first few days and build up to my recommended dosage.

If you experience fatigue, lethargy, irritability, nausea or other uncomfortable conditions when starting with chlorella, try reducing the amount you are taking and build up even more slowly, as these may be symptoms associated with your body cleansing itself. However, if the symptoms are severe, or if they persist despite very low initial quantities of chlorella for the first few days, stop your chlorella regime and discuss with your personal medical practitioner.

Also please note that if you are a protein metabolic type these problems might be more severe and you should start much more slowly with one-half or even one-quarter capsule and increase the dose very carefully and slowly. Carb types seem to do much better with chlorella.

Caution: About 30% of people cannot tolerate chlorella. If at anytime one develops nausea or starts "burping up" the chlorella taste, then the chlorella should be stopped immediately as a food sensitivity is developing that will only worsen if you continue taking it."