How does one cope with despair using Buddhist practises?

I had rather severe melancholia for some time and I still feel deep despair occasionally. For example, today, just after the workout and a good meal, I felt severe, yet inexplicable, mental suffering. No one offended me or anything bad happened recently, but I could not relax or concentrate on something. I just felt anger (not to anyone particular), self-pity and deep dissatisfaction. I wanted to pop tranquillizer firstly but instead decided just to sit down and practice open-monitoring meditation. I cried a bit, but these feelings have largely gone and I feel calmer now (though not happy for sure). Every day I feel this subtle dissatisfaction and it often progresses to those hysterical outbreaks (uncharacteristic for males, I know). Despite that, I feel mostly drowsy during the day, not nervous, but this is quite another problem for which I think meditation on breath is the main solution, as it helps you stay awake and more concentrated. Is open-monitoring meditation the best idea when you feel you are about to cry? I thought about Metta meditation, too, but wishing yourself or anyone else happiness sounds like a joke during those outbreaks. I often practice Metta before sleep though. So what would you recommend on preventing and "treating" these hysterical reactions? You know, psychiatrists and psychologists have nothing to offer to deal with it, except for the drugs...