Hello dear, to calm your chattering mind, i would recommend breathing exercises and meditation. After just a few days of breathing exercises you will observe that your mind has quietened down. You might still get negative thoughts and emotions but you will becone aware of them and even when you have a weak moment you will be able to come out of it sooner. I would also recommend keeping a daily journal. Record objective observations regarding your thoughts and circumstances including if you had bad mood on empty stomach, when you were tired, or the events leading to it. This will help you recognize a pattern on whats going on, what's triggering your thoughts and moods and also give you an objectivity regarding what's going on. And then proceed to resolve them from here . Also, in another journal perhaps try recording all the positive things you have experienced. This will hell you to have good memories, reduce your cortisol levels and negative thoughts and will definitely relax you. Hope this helps you.