I haven't been successful with meditation because I can't concentrate. You might benefit from seeing a therapist. Don't be discouraged with meditation. You need to bring yourself back to concentration every time you lose it. You might need a good meditation teacher.
Many yoga classes combine relaxation, muscle stretching and breathing exercises.
You only get better with practice. You can strengthen your mind to be focused, alert and relaxed. My favorites are muscle relaxation, breathing and meditation. I also find that regular exercise reduces anxiety and stress. Most of us will build up our stress levels throughout the day, day after day, and unless we take active steps to reduce stress, we will eventually get to that burnout threshold where we feel very anxious.