What do you think if I tell you that I feel like the bad person?
Why would you feel this way?
Because I feel like cutting someone out of my life
Everyone gets into conflict with someone else from time to time.  It's totally understandable that you'd be feeling down over it.  Don't worry, it'll pass!
I feel like I'm too weak to cut someone out of my life. I'm getting more negative in life.
You definitely sound like you are having a bit of conflict. If the person is not good for you, you should not feel guilty about cutting them out. At the end of the day, it's about you and your happiness.