How to stop overthinking about everthing?

For example, i gossiped About a guy that was a jerk to me but then a girl told him what we said and i started to overthink, as usual, and felt horrible. I sent him a facebook message explaining why and that i felt bad and stuff. He replired a stupid comment then awhile later said im not being mean i mean that i believe you but He then ignored me and never spoke to me... i cant stop thinking about it and when i sent a message to kinda break the ice (not creepy, just an inside joke) he never replied... i keep overthinking this situationand its ruining my summer:( i would blame it on OCD but im not sure if that is the cause. Please help me with this so i can return to reality! O.o