Can't personally relate to this as Metta always made me happy and mindfulness of breathing only brought calmness. But you might want to try Satipatthana meditation as it focuses on senses at their basic form, rather than perceived entities.  I believe being emotional is always connected with people and the notion of self. 
But if you can note seeing as just seeing, hearing as just hearing, sadness as just sadness etc. you should become less emotional.