Staying cool, staying focused

Back from a long weekend.
I've been having some issues with anger lately. Namely, I constantly get annoyed by little things but suppress my emotions in order to remain calm, or at least appear that way, and eventually all that pent up frustration comes bursting out in the worst ways. I just want to stop getting annoyed at all the little things. What good is staying calm in the face of adversity, large or small, only to explode a couple days later over something like a broken crayon? I can't seem to figure out how not to have the initial reaction of frustration, anger, etc. when something happens.
I was thinking about this problem on my drive home this weekend in context to volunteering. I want to be able to offer help to people regardless of their situation or motives, as I believe Dorothy Day did. She believed that dealing with difficult people was a sacrifice to be offered up and you shouldn't shy away from offering services to (or working with) those whom you don't like or agree with. If I can't seem to deal with the daily stresses of raising a family, how am I supposed to deal with people, whose problems (physically, financially, emotionally, etc) far surpass mine? How do volunteers not get frustrated and not want to give up? The problems that Day faced at the early part of the 20th century are still with us today and will be long after I'm gone. Can I really make a difference? Does helping some poor people in an inner city really effect the larger picture? Should I really stress myself out doing this? Will the people I want to help even care if I'm there? Why should I bother if they don't?
I suppose I know some of the answers. Jesus calls me to serve others. I don't really need any other reason. I know I need to pray for the grace to accept people as they are and not get 'stressed' out in the process of helping them. Maybe I haven't been praying enough and that's the root of the whole anger thing entirely. I'm totally due to hit confession. And maybe some of it is fear. I've identified a goal but there's a hesitancy on moving forwards in such a new direction. It feels like the journey I took towards joining the Catholic Church. I knew it was right but I couldn't just jump into RCIA the moment the realization hit.
So pray for me. I need to mellow out. There is a larger picture I've lost sight of.