So many negative thoughts

I realized I have so many negative thoughts. I used to assume I had worries/negative thoughts about just a few things. I paid attention to my thoughts and found I was being negative about so many different things. Then my thought went to “If I have this many negative thoughts about so many different things, that is why I feel bad so often”. I also thought about if I am needing to feel better to act better (lose weight, relationships and all the things), how can I when I think negatively about so much? Your wisdom is appreciated.