Yes, it's tough to accept a Bipolar diagnosis.
Sometimes, this is more difficult because we may not understand how BP I and BP II present. Even if we do understand this, we may not have insight into our own behaviors/experiences.
Then there's the stigma.

People seem to more readily accept a friend having a diagnosis of depression over a diagnosis of bipolar.
It definitely takes time to come to grips with a bipolar diagnosis and even if/when we do adjust to it (accept it), we often keep it a "secret" due to the stigma.

WC