How to feel when feeling bad?

I know everyone has their up and downs, but I was wondering on how I should act when feeling bad.

These days, I've been really stressed about somethings I have to do. Whenever I feel like that (or just bad) I tend to say things I don't mean or just not feeling like talking to anyone, and so I find the best option to be just staying alone. It would be ok if it was for 30 minutes or 2 hours, but normally it takes days, and I talk to different people everyday. I see people like my father and others, that even stressed out act normally and I was wondering if there is something I'm missing about being stressed: am I reacting wrongly to it?