Your symptoms could be a part of depressive illness which is typically believed to be due to deficiency of serotonin and norepinephrine in brain cells. Though deficiency of these neurotransmitters is hypothesized to be a cause of such symptoms , studies have not found an absolute decrease in levels of these chemicals in brain. Hence, there might be other mechanisms which might be responsible for such symptoms. At present there are no clinical laboratory tests to identify levels of these chemicals in your brain. Consult a psychiatrist to find out what is the cause of your symptoms.