I have a problem of overthinking.

Hello, Impairment in sleep is highly related to low mood and depression. Depression can cause sleep impairment, and it is also possible that insomnia is causing depressive symptoms. Hence my suggestion for you is that please seek a consultation with a psychiatrist near you for comprehensive assessment and further management. A comprehensive assessment will throw more light on the symptoms and further management can be planned accordingly. A psychological intervention is definitely requires you, whether a medicine is required or not can only be said after the assessment. However please be well assured that your condition can be helped with proper guidance and treatment. Hope this helps you. Best wishes for your health and future.