ok, seriously, i have a problem overthinking. it got to a point where i just didn't say anything anymore because i was too busy thinking of what i wanted to say. i also play varsity basketball and i constantly overthink situations there too, until i finally realized that my overthinking was holding me back not only as a player but also as a person. my coach told me that i just needed to let things happen, and react by instinct because most of the time, we already know what to do and say, it's just a matter of having the confidence to do and say it. so don't let this control you, it's not worth it because you won't be able to experience the best things in life if you're already expecting what is going to happen. just remember, its ok to think, just make sure that you leave room for flexibility and relaxing... leave a little surprise and spontaneity in your life. it'll be worth it in the long run... I still overthink once in a while, and believe me, its a pretty hard habit to break...just know that you can get over this over time, not overnight.
i hope this helps as much as it has helped me.