First of all, anything is possible, and I'm sure you will be successful in whatever direction you choose, whether it be teaching or somewhere else.
But just out of curiosity, how far are you into your major if you do ultimately decide to change? You sound very sweet, and I'm sure you will be a great teacher. As others have mentioned, it is possible to be a teacher and have bipolar disorder. Heck, it's possible to be anything and have bipolar disorder. As long you're stable and keeping regular appointments with your pdoc and T to help with any stress that may arise.
Good luck!