When I was finally diagnosed, it came at a point where mentally, I snapped. I couldn't readily control my actions, stop the racing thoughts, or rationalize well. Bipolar is the typical fluctuation between the Mania and Depression stages. The duration, frequency, and severity of these stages is what determines the specific type of Bipolar you may have. Typical Mania behaviors are those that are typically rationalized and controlled under normal circumstances, but can easily become uncontrollable and life altering if left untreated. Some typical behaviors can include the involvement in unusual risky behaviors, financial irresponsibility, sexual promiscuity, and agressive/assertive behaviors. Mania stages seem to amplify the natural curiosities and tenancies to partake excessively and (almost) uncontrollably.
On to depression... if kept unchecked, it can consume you. There is no set time frame for any one episode and the intensity varies as well. Unfortunately, if left untreated, it becomes a vicious cycle of poor behavior choices leading to regret and depression for those associated behaviors. Nothing will excite or interest you while in this stage, but it is important to try to pursue SOMETHING that could help deviate your thoughts. Surround yourself with friends and loved ones... if you are diagnosed, encourage them to read up on bipolar so they can understand the struggles both and them will go through. A support system is important...
Finally... it took 2 hospitalizations, 3 Psychatrists, and numerous therapists to determine I am Bipolar. Mine was an extreme case that came about under heavy stress and duress. While its great to finally have an accurate diagnosis (Doctors thought it was 'Seasonal Depression' and Social anxiety), it does label you in public opinion, insurance circles, and medical fields. I take 4+ medicines, see a Psychiatrist every 3mo. and a therapist bi-weekly. But, I'm able to treat it and recognize it WAY more effectivly than before. It's a give and take relationship while finally having some piece of mind... I hope this info helps. :-)