how do i stop worrying about the things that don't matter?

Focus on more important things to get your mind off them. I know its hard, I constantly think about things that don't matter but I try to focus on things that are now in my life.

First remember to breathe. Second understand that our human minds want to protect us and need to be gently reminded to quiet down. It is natural for our thoughts to run wild, but when we are mindful of what thoughts don’t serve us, we can manage better. If a thought keeps popping up throughout the day, ask yourself is this relevant to my life right now? If not, then say, not going there right now and smile because you just intervened an unnecessary worry. Give yourself time to practice this and be kind to yourself when your mind wanders where you prefer it didn’t. After all, you are only human. I do love affirmations too. Such as, I am living my best life. Try that when you notice your mind goes to that place you don’t prefer. Hope this helps.

Take a deep breath and find something to do to get your mind off it (i.e. take a nature walk or do a craft activity).

First, if we are worried about something, it's because it does matter. The important thing is to go to the root of why I feel hurt.

You look at what is good in your life focus on that and remember it may not be prefect but it could be worse

Try to work on a mindset of your current and what you'd like to focus on in the present or future. This can help with distracting yourself from things that aren't relevant to you as of now.

You can actually do that by getting involved into other innovative things which will be beneficial for you and frm which you can learn from this will keep you busy and engaged in other things which will have a positive result

i try to do brething excercises and then think about the things that are not in my hands to get fixed.

I always use this method to figure out if I should try and let go of something I'm worrying about. I ask myself "can i do something to change the thing I'm worrying about right now?" If the answer is yes, then there's no need to worry because I can take actions that will help relieve my worry, and if the answers no, then that means whatever I'm worried about is out of my hands, so worrying about it is kinda useless, because no matter how much I worry, nothing about the situation is going to change.

I can not give you advice on what to do, as only you know what is best for you in your life. With that in mind, I actually may have experienced a similar situation as yours. I used to worry about everything, even the little things. I felt I wasn't in control. How I came to stop, or at least reduce this was a process. Over time I realize that I shouldn't stress the small things, as they aren't in my control most of the time. I learnt to let go. What if a friend, or maybe a sibling, was constantly worrying about everything? What would you tell them? Think of ways you could establish serenity and calm into your life and implement them little by little :)