Sadness. Irritation. Emotional outbursts. Feelings of uselessness. What do these together mean?

Eval. This constellation of symptoms could be consistent with a mood disorder. Consider a comprehensive assessment by a doctoral level clinical psychologist or by a psychiatrist to better understand these symptoms.
Eval. Get yourself a full psychiatric evaluation to find out what bothers you, and consider medication as part of treatment. Seek out a reputable psychotherapist to discuss when emotions mean to YOU. Dontt rely on just meds or just therapy. For optimal effect, both should be used simultaneously.