Stuttering is not an easy problem so solve. It can get better as you get older, and often does, but not very quickly. Meditation and relaxation exercises? Well, those might help, in the same way a placebo might. You will learn how to get really relaxed while you are relaxing. It may not help at all when you are working, and not relaxing. I would advise going to a speech therapist if you can afford it, and most speech therapists are affordable. A couple of hours a week of therapy is probably enough, as it is combined with self-work. Assuming you are employed, this is money well spent. But do not expect miracles, even from professional therapists. You will learn techniques on how to get past blocks, and this can help, but be prepared for relapses as well. But at least you will get tools on how to deal with the problem. One technique that helped me was called gentle onsets, and I practiced it a lot. In sum, you sort of ease into the first sound of the word, and you practice it with every sound, so you can do it on any word. Like with M, you can start out humming. It obviously works better with some sounds than others, and can sometimes sound a little unnatural, but fluency is the goal, so that is OK, in my view. This is just one technique, and you will learn others. You can learn these on the Internet too, but having a live person to guide you is worth it, in my opinion. Good luck and keep your chin up!