Bipolar does tend to run in families, but that doesn't mean that if no one in your family is bipolar then you are immune. I have my suspicions of who might have bipolar in my family, but nobodies talking... It is also true that thyroid problems can read like symptoms of bipolar and usually a doctor will check your thyroid. I've had my thyroid checked many times and it is low normal. My mother was just dx with a thyroid problem and has to be medicated. It is also possible that you got hit with two whammies and you could be both bipolar and have a thyroid problem.

There is just no way to know for sure without going to a doctor. If you are concerned about being dx bipolar before you are 18 you might want to see if you can still have your thyroid tested before then. With thyroid issues running in your family it wouldn't be a far stretch to want to have it done. Then again getting dx with bipolar sooner means you get to start working on finding the right meds sooner and begin to feel better sooner.