SENSE & SENSITIVITY DEAR HARRIETTE: I have a puppy. I’m happy about it, but at the same time, I feel bad. I am in school, and I work almost every day. My puppy ends up staying in a kennel for 10 to 12 hours a day while I’m away. When I get home, he is so happy to see me. I spend some time with him, but I’m so tired I don’t really have the energy to play. Plus, I often go out at night. I’m 20 year…