I went through a phase for quite a few years where I was very angry and bitter with everybody.
I'm not sure what will work for you, but in my case, I had to examine the emotions underneath the bitterness. I soon realized they were the protective layer for feelings of disappointment, resentment, and sadness about unmet hopes and expectations.
I had to work on meeting my own needs and get rid of people and situations that weren't healthy for me. I can't get rid of family, but in some cases I had to limit contact. I got rid of toxic friends and worked on unhealthy beliefs that made me believe I wasn't worthy of having good people or experiences in my life.
It's taken a few years, but the bitterness is mostly gone.
If you ever want to talk sometime, feel free to contact me.