I think the first thing is to accept it -- then move onto therapy programs that can help you cope with daily emotions.

If you REALLY don't believe you have bipolar disorder, try to keep a mood chart for a month. Record any drastic mood changes and mark whether or not something upset you to change your mood. If you're finding that mood shifts are occurring because of things that happened in your day then it probably isn't BP. If the mood stays stable or alters without reason it probably means its bipolar. Regardless of what it is, its important to learn coping mechanisms to deal with the ups and downs. A lot of the people who are fairly stable off medication have done a lot of work in stabilizing their emotional state, too.

I hope this helps a little.