Thinking: can't live with you, can't live without you

I have been told many a times by my father that I think too much. Put too much of mental effort on every problem. According to him, I am so much afraid of being deceived, that I am not enjoying life per se.

Recently. I have been thinking (haha) that he is right. Like someone said in response to define poison, that excess of anything is poison, I feel right now, too much of thinking is injurious to one's health.