I have anxiety and overthinking problems and they are affecting everything in my life including my grades and sleep.

Uh well, it's like- for example I lose on an online game and I typed in chat once, I feel like I made my team lose by typing and not focusing enough and it seeps into my thoughts where I imagine them going "my team mate did nothing but chat" and then I feel guilty and overthink about it and think they hate me or uh my friends dont respond for a few minutes and or act a bit different and I keep thinking that they have a secret chat where they talk behind my back.

Or my classmates hate me for getting the answer wrong in class 2 times 

Or everybody thinks I'm dumb and empty headed for accidentally giving the wrong change at the store

Or the sneakers I wear is why everyone will stare at me and secretly judge me for.

All of this makes me stay up at night and I need advice