Anabolic enlightenment. Dilemma of mine!

I've been working out for 4 years now. After great progress I've sadly plateaued. I'm a vegetarian and the only source of protein is whey protein shake or dairy products or maybe some pulses. I need advise on additional supplementation. I have been contemplating between BCAAs, glutamine and creatine. Although I'm aware that creatine is the most superior of the 3 but I've read that it needs alot of attention while cycling one's self with it. Glutamine and BCAAs on the other hand are supposedly good for muscle maintenance. So now I want some guidance to help me choose the correct supplement. I'm very clear with my goal of gaining muscle size and strength and I've also been working out rigorously. So no worries on the training part. Would really appreciate if someone could help me with this dilemma of mine