When I was a first year graduate student, a supervisor of mine gave me a book to read by Pema Chodron. I was experiencing my own "growth" as a young adult, while also trying to learn and put into practice the therapeutic techniques I was learning at school. To say it was a tumultuous time is an understatement.
I cherished that book, recommended it to colleagues and friends alike, and found myself returning to it throughout the years. The truth is, we ARE actually in charge of our emotions and reactions. Of course it is easier to succumb to reactionary feelings when we find ourselves outraged, slighted, hurt, etc. But, it truly is the braver thing...the more peaceful option, to realize that we will actually find our own peace and solace within ourselves. We cannot control what other people choose to do in their own lives as they are fighting their own battle of anxieties, stress, and responsibilities. All we can do is choose to NOT let their decisions dictate how we feel and alter our sense of self.
It will not always be easy, but it starts with some self-compassion and recommitting to this mindset everyday.