Dilemma...maybe

Since when I become so bad at expressing myself or my opinions. Maybe since I left university. Seems like when I graduated.I left out a lot of important things. Since I graduated I rarely participated in anythings. I just go with the flows as my friend said. Graduated - interviewed - posted - and now teaching for almost two years. Can I blame the environment at school? or should I blame myself? I'm restraining myself a lot at school. And I started to care so much about what other people's will say. Is it patience or is it being a coward? I have a lot of things in my mind but I can't express it somehow. Sometimes I feel like I don't have anyone to talk to. I also feel like that I'm getting bad at the things that used to be good at.