I only care about my own comfort and don't want to help others

I am 16 years old, I often feel callous and selfish to the core, and this depresses me, even scares me.

I can’t sympathize, I constantly have to pretend, it’s very hard, often I just sit nearby silently, looking down and don’t know how to express sympathy, which is not there! There is no question of reassuring a person at all, I just don’t understand how, I choose words, but discard them, thinking that they do not fit.

I am selfish. I constantly think about myself, about my convenience. Moreover, I believe that each person should take care, first of all, of himself, if possible without asking for help, which I do, I don’t often ask for help. If they ask for help, I react differently. Sometimes I do it with joy, but often the requests of friends and relatives make me angry and annoyed, I feel sorry for my time.

I really do not like that I treat their requests in such a way that I try to evade or indirectly express dissatisfaction, but I continue to do so. I don't like it when my parents get sick and ask me to go to the test-antibiotic.com store, go to the clinic with them, etc. I get very angry (but I don’t express it to them), I don’t feel any sympathy for them.

Compared to my parents and some of my friends, I just feel really mean. I never express my dissatisfaction with the person asking me, but I keep it in myself, sometimes I whine to someone or write it on paper. Maybe it will go away with age?