I've thought exactly like you in the past. You have already identified your problem - negativity - which is a huge step. Over several years, and it's a constant thing even now just like brushing my teeth, I had to change my inner monologue to be positive and uplifting rather than pessimistic and negative. I used to make a lot of sarcastic jokes that verged on mean, and I generally had a more biting attitude toward things I didn't like. None of that, plus my views of myself as lesser because of my stutter, was helping me in life. Every day, I tell myself how I think. I tell myself how I should be reacting to situations. To the extent possible, I no longer spend any mental time thinking about bad things, feeling sorry for myself, stressing, etc. I take care of whatever business is in front of me and keep my mind in a happy place, whether it's thinking about a favourite hobby or whatever else. A negative outlook will make a negative life. I think from your responses you're actually moving in the right direction, even if it's very challenging right now for you to believe there's a light at the end of the tunnel.