Is it true that the cruel world and people around me doesn’t care about anybody else but themselves,

I just don’t wanna believe my dad and my adult siblings when they tell me. I was upset about something and one of my friends said, “Look we’re having a fun day so it isn’t worth crying right now.” And she walked away when I needed her. We were having a fun day and nobody even comforted me when I was upset. They were too busy having fun. I went to my teacher and she asked, “Okay why are you crying?” And I explained about my mom abandoning me. She looked annoyed and said, “Look sweetie that’s the past. You need to move on from that. Your moms loss. Here talk to your friend. I’m not doing this today.”
Wow I though she would be understanding. Why do people walk away when I cry and have a problem. My oldest brother said, “Look, people have their own problems to deal with so they don’t really have time to worry about yours or they just don’t give a damn. Not everyone is going to care about your problems or your feelings. That’s what dads been trying to tell you but you don’t wanna listen and your problem is you wanna live in La la land and want people to sugarcoat things for you but it won’t get you anywhere in life. You can’t handle the truth or reality so you better shape up and buckle down.”