Am I taking life too seriously?

Brother and sisters came home for dinner. We are all talking and joking. My second sister mentioned that my coming home with my sons has created some grief for my youngest sister. Just then, my youngest sister had tears in her eyes. Feeling guilty, I asked if if were my fault. My second sister claimed that they were just joking, and that I am taking things too seriously.
Later that night, my second sister came into my room to have a talk with me, yet after the conversation, I felt more lonely and confused than ever. She told me, not to take things too seriously. She said many people run their life differently and that they might present their attitude differently. She continued saying the only reason she and my brother continue to live on my father`s expense is because he is able to afford it. This and a few other statements still confused me. I am taking life too seriously because I care about how my parents think about me? I am taking life too seriously because I want my father able to retire when he wishes instead of supporting his grown children?  I am taking life too seriously when I care about my youngest sister`s feeling?   
May be I am taking right and wrong too seriously...