"It isn't the mountains ahead that wear you out; it's the pebbles in your shoe. Muhammad Ali." Everyday distractions take you off course, and you trip on each pebble that is a "what if" or "what could have been." I did this a lot in my life, and do it even today. However, when negative energy is changed to positive energy, the mountains are easier to attain. Only you can change the perspective of your day.
Concentrating on negative "thoughts" bring negative expressions and feelings, and it is a one-way street, unless you choose different. Try to remember that they are only "thoughts," and can be eliminated or adjusted. What you have learned over time, can be unlearned. You have to do the work. Continually ask yourself when you have a negative thought, "Is this real?" "Is it only a thought I have?" If so, work through it to find the source of discomfort or pain. Find a balance of what is real and what is not. Acknowledge it. Don't wallow. Climb up that mountain, even baby steps, with confidence and assurance. Others have walked/and will walk that path with you. YOU'VE GOT THIS!!!