Is it right to feel like this?

Sometimes I feel like im the black sheep of the family ever since my niece was born it hasn't felt like it used to I feel depressed now I can't focus my feelings are mixed up I just don't want to be here but I'll keep going today I felt completely lonely my friend were doing something and I couldn't participate because I didn't like hot food and they all shared chips while I just watched im completely alone in my seat at school things aren't much better at home all the attention is on my niece I know she's a baby but even my parents love her more I feel compelled done..