Hey,
I think it depends on what makes you feel awful / what has happened. But in general I try to not bother too much about things going bad, if I can't do anything against that. If you can't fix the problem, you should not be too worried about it. "It is what it is" sometimes ;)
Just remember that life can be like a roller coaster and goes up and down all the time, which is great, as it would be way too boring, if everything went as planned. Imagine everything you plan a certain way, just happens like that - it would get boring at some point, so things going the wrong direction is just a part of our lives and makes good moments feel even better.
So I would just recommend to keep in mind, that it's important, that not everything is going to be as planned and that you will have to move on, instead of destroying yourself by thinking about it too much. Maybe watch some funny videos or plan something else that makes you happy for the future, as you can't change what has happened.
I hope you can understand me and I could help you a little bit.
Best of luck! :)