effectiveness of mantra

I feel so, pessimistic today!every action I make is getting messy and i hate it!tomorrow will be our preliminary exam and I'm not ready with it I did not also studied my lesson ahhhh! I can't understand myself. there's something wrong with me. After a few minutes I realized that it's already been months that i haven't take a meditation. That's why i decided to go to my room and have a deep meditation maybe in this manner I will be able to burn those negative vibes in my head that disturbs me. When I'm having my meditation at first I cannot focus and concentrate but i tried very hard to focus with my mantra.then after 30 minutes of meditating I feel relaxed and satisfied..ohhhhhh!what a bliss!It made me realized that just a one snap then walah!He's there right away to make me feel that I'm not alone and that He will never leave me when I'm troubled.