overthinkverb [ T ]
uk/ˌəʊ.vəˈθɪŋk//ˌoʊ.vɚˈθɪŋk/to think about something too much, in a way that is not useful:
I overthink everything and worry too much.
overthinking
noun [ U ] uk/ˌəʊ.vəˈθɪŋk.ɪŋ//ˌoʊ.vɚˈθɪŋk.ɪŋ/
Often it only takes a minor event to spark off a spiral of overthinking.