Ugh, I'm tired of people treating me like trash. I think I am a coward who allows people to walk all over me. I hate myself
Why do you feel this bad about yourself? Did something happen in your past?
Yes, I regret it so much. I would want to change so many things about myself.
You shouldn't let people walk over you, but if they mistreat you in this manner, that is their fault.  It doesn't make you a coward if they are disrespectful, but if you hate yourself, you could benefit from talking to someone about your reasons.
I know, I just really hate myself.
Have you ever tried counseling or life coaching? Either of those things could be beneficial in helping you be more assertive and have more self respect.