I overthink things too sometimes, I usually worry about how awkward I look or overthink what I want to say (usually to the point that I don't even say it) I worry about about my words coming out jumbled and stuttering and sounding stupid, appearing awkward/nervous/uncomfortable/cold and making people feel the same... because of this I usually avoid talking all-together (this is in group situations though, I will talk to people in one on one situations and how I feel and whether or not I overthink depends on who I'm with) if I do talk and make a mistake then I definitely overthink it about afterwards and feel very anxious and beat myself up and will want to avoid similar situations in the future.