Given that 40 million adults in the U.S. have some kind of anxiety disorder, how to stop worrying is a subject worth reflecting upon. It's a huge waste of time, energy and productivity considering that the vast majority of things which you worry about never happen and usually are completely out of your control. Here are several actions which you can take right now to stop worrying about the future.
Realize that worrying makes your brain feel (wrongly) like it's doing something productive
Yes, your thoughts are spiraling and your rumination feels like you're doing mental pushups which should count for making progress toward a solution. This is not what's happening. The mental drain which you're experiencing is from repeatedly allowing thoughts which are not serving to make anything better.
The deep breathing you're not doing really will help you
If anxiety is something you deal with every day, deep breathing likely has not become a habit for you. Personally, I use Dr. Andrew Weil's method of deep breathing and find it effective in calming my thoughts, lowering my heart rate and getting me into a better headspace. To do it, breathe in through your nose for four counts, hold your breath for seven counts and exhale through your mouth audibly for eight counts. You should be doing this at least twice a day, in the morning and at night.
Stop your automatic reactions by understanding that your subconscious brain is always on the lookout for threats
Thousands of years ago this often was some kind of physical danger. But today, social threats can incite an automatic fight-or-flight response which isn't always helpful or healthy. According to Kerry Goyette, author of The Non-Obvious Guide to Emotional Intelligence, common social threats include lack of clarity, competing priorities, lack of autonomy, fear of failure, lack of recognition and validation as well as a lack of fairness. These kinds of threats then trigger derailing impulses which include conflict avoidance, impulsiveness, blame-shifting, control, perfectionism and power hunger. You need to be able to pause and reflect upon what's going on within yourself, others and your environment. "To prevent these derailing habits, it's essential to know the triggers that will set you off," she writes. "These might be situations, comments from others, or interactions with certain content or messaging."
Get yourself some CBT
Maybe you have excuses for not getting help from a professional, but as someone who has worked with one on issues involving anxiety, I can attest that cognitive behavioral therapy really does work. I saw a therapist for about two years and countless times he would point out errors in my thinking. I still have a printout he gave me with 10 cognitive distortions or irrational beliefs which people commonly hold and reinforce over time. It's important to realize that many of your habitual thoughts are erroneous and not helpful to you in any way.