Books to help becoming mentally stronger

In my day to day life I have come to realize that I am less mentally strong than what I thought. Meaning that when I receive several setbacks my motivation starts to waver and I just find myself crawling. Sometimes, even though rarely, I had some negative thoughts. Also the type of thing where in competition, between friends for example, I start to overthink. I'd like a book, or even a podcast or whatever, that could help me becoming more mentally strong. Thank you in advance!