To refer to your mental health status as mental illness, the signs and symptoms faced by you would have distressed or interfered with your professional or personal work and would have lasted for a definite period. Each mental health disorder has its own set of signs and symptoms that differ in severity, but some of the common signs of mental illness are Mood swings, difficulty to focus – make decisions, change in appetite, withdrawal symptoms, anxiety, panicky, feeling guilty, sad for no apparent reason, and suicidal thoughts. It's important to note that the existence of one of these indications does not necessarily imply that someone is suffering from mental illness. But it does indicate that he or she may need a diagnosis or further evaluation.