Working with people

I'm a very much a "go at it alone, and do it right, do it well" kinda girl. But at the high school we work in teams. This bugs me because I very little control over what we teach and when. Right now, the person who is supposed to be creating the plan hasn't created the plan yet, and so I have no idea what I'm supposed to be teaching on Monday. I'm a long term planner and this bugs me to no end. I really like my department, but I have a very different personality than the people I work closely with and this creates issues for me as I adapt to their personality types. It is very frustrating for me today as we were in professional development meetings. It really just rubbed me the wrong way. They are probably oblivious (and rightly so) about why I am pissed. But I so am. I'm a very opinionated person and have good ideas, but I'm too frick'n polite about things and worried about stepping on people's toes to be assertive with them.
Gah! I'm my own Catch-22