It sounds like your mood problem is situational? Or maybe just coincidence that the breakdowns are at home? It could be that there's a trigger (or stress) at home that pushes you over the edge and into an abnormal mood swing? Triggers vary from person to person. What's your mood like before you fall into depression? Experience any severe irritability, agitation, anxiety, more easily distracted, etc.?

I had one yr in college where I could not take tests. Very easily distracted and would lose my concentration. (Stuffed in room, arm-to-arm with 125 people, people coughing, turning pages, dropping books. Everything seemed amplified.) Got two Ds, two Fs. Next semester was worse, I cracked and took a leave of absence.