The only thing that keeps me from hurting myself is I feel like they wouldn't care anyway.
Why don't you think they would care?
I don't care about them, so why would they care about me?
Everyone feels down from time to time, but wanting to hurt yourself is a sign that you need to talk to someone immediately. Having those feelings is not good for you and you should talk to a therapist as soon as you can. They can help you through this and help you feel better!
I shouldn't need to talk to a therapist. If I want to stop I will.
I can understand that you are feeling down and everyone gets that way. You should not want to hurt yourself because of it. You could always spend more time with friends and talk things through with them and help you get out of this funk.