Spirulina and Chlorella are completely different...besides that they are algae. Spirulina is actually shaped like a spring and chlorella is round I think with a cell wall we can't digest so it needs to be broken open somehow...usually with a high pressure spray of water.

Its all on how you react to it. Like any food, its probably not good for everybody. If it gives you energy and makes you feel good (it should), then keep on taking it.