Scooby, you CAN have depression and not know about it. Some people have biochemical depression without the feelings of being sad, down, blue, hopeless, etc. and experience it instead as irritability, crabbiness, and being short-tempered. Some people experience it as fatigue. The research is fairly definitive about neurotransmitter problems having a key role in depression, altho the direction of the causal arrows between life situations and decreased levels of the neurotransmitters seem to go both ways. But, all that aside, hooray if you don't have it!!