No. You don’t just end it. There is no “just” in ending. It’s a mistake you can never undo so let’s find other solutions to your problems, okay?
The people at school who say you can’t be depressed because of your race are just plain ignorant. From what you wrote, you have very real reasons to be depressed. You are probably still grieving the deaths of the two beings who understood you and supported you — your pop pop and your cat. You are being bullied and the people who should be helping you with that aren’t doing what they should. Your family members are so caught up in their own stuff that they aren’t there for you. And you have a significant health problem. It’s no wonder to me that you feel depressed!
Hoping for a better life probably won’t make it happen. You are going to have to step up and take charge of your own life.
The first stop is to your doctor. Make sure there isn’t a medical reason for being overweight. If you already know that you are taking in a whole lot more calories than you are using, it might be helpful to go to a nutritionist or to an organization like Weight Watchers to help you change your eating habits. Eating well will be a positive step toward feeling better.
Then on to the even more difficult stuff:
Bullying is serious. Fortunately, we are now living in a time when school administrators are generally taking it seriously. I imagine there is a counselor or nurse at school. (It not, go to the teacher you trust the most.) Make an appointment and talk about the bullying. It’s asking too much of any kid to tell them to just deal with it. Ask for help making it stop. If that isn’t possible, see if there is an option to transfer to another school where you can make a fresh start.
As for the family issues: Many, many people don’t get the family they deserve. Sadly, you are one of them. But that doesn’t mean you are doomed to be unloved and unsupported. It does mean that you need to take steps to find people to be your own created family.
Identify people you admire who you would like to be closer to — like a teacher, the parents of a friend, a coach, etc. If you don’t have someone like that now, get involved with a club, activity, service, church or other organization where you will meet good people who have room in their hearts to befriend other people. This is a project that will take a while. You may not be successful with each person you try to get closer to. But, believe me, this is worth doing. Family is a feeling, not just a blood line. If you find other people who share your interests and passions, you will eventually find a “family” of friends.
Finally — Stop trying to be your own therapist. The girl in the mirror is an amateur. Ask your school counselor or clergy person or a trusted adult to help you find a counselor. Many cities and towns have programs for adolescents that provide free or low cost treatment. You deserve to have someone in your life who listens to you, affirms your strengths, and helps you learn ways to solve and cope with problems.
I wish you well.