I feel the same man, just turned 20, in college, but my social life in non-existent. I had friends my first year(which i've always made friends rather easily because my easy going nature), but they have all left for one reason or another. My advice to you, which has helped me tremendously in my thoughts about my speech is, meditation. Whether it's sitting quietly and actually meditating or reading some stuff on buddhism or taoism. These things calm me down and help with my perspective. Life is life, man. If it wasn't sututtering, it would be something else. There is always a struggle; hang in there and do not give up. Being submissive to your problems makes you a slave to them. Liberatw yourself, best of luck