You cannot change either the past or the future. But you can control the present moment, and this should always be your focus. The present moment is where living is done. Any action (in the present moment) towards your goals is often better than no action, particularly if you are not achieving the things that are really important to you. If you do the right action, that is terrific. Even if you do a wrong action or make a mistake, you have learned something, and you can change it next time to progress. If you do nothing, you learn nothing.
It is the same with martial arts. I used to really stress about sparring before each session. What if I get embarrassed? What if I get injured? Even though I had never been seriously injured in sparring before, the thought of sparring always used to worry me. I was living n the future and worrying about things that may not happen. It was affecting my present moment. It took a lot of training before I started to accept that I cannot really control the many variables, particularly future potential variables. Instead, I learned to embrace the present moment, get in there and enjoy the experience. And my martial arts greatly improved as a result.
If you can learn to embrace the present moment in the dojo, you can certainly do it with other areas of your life. As Eckhart Tolle said in his great book, The Power Of Now, “It is not uncommon for people to spend their whole life waiting to start living”. That is because people are not living in the here and now. Do not be one of those people who never live their lives. Decide what is really important to you, constantly focus the present moment, and start embracing the “here and now”.