Emotional abuse can be hard to define. It can include name-calling, insults, manipulation, humiliation, and generally making someone feel bad about themselves. You can find some articles about it on the internet and here’s one from Psych Central: https://psychcentral.com/blog/archives/2013/02/20/signs-of-emotional-abuse/
Based on what you describe in your question, I would say yes, you are being emotionally abused. Your grandma might not realize she is doing it and might not be doing it to hurt you. It may be more about the way she was raised herself or she might be under a lot of stress.
However, that doesn’t change the fact that it is hurting you and it’s not okay. Have you ever tried talking to her about it? Let her know that the way she talks to you hurts your feelings and makes you cry. If this doesn’t help (or makes it worse) I would suggest that you and your grandmother seek some family therapy from a mental health professional. If your grandma won’t go with you or won’t help you find one, you could ask your school counselor for help. They may offer some counseling at your school or they can at least help you find someone in your community who works with teens your age.
It’s also important to get support in other places, like from your friends, your pastor, a teacher, or another trusted adult. The important thing is to reach out.
Please remember that this is not your fault and you don’t deserve to be treated badly. I hope that you and your grandma can work through this and develop a more loving and supportive relationship.
All the best,
Dr. Holly Counts