Axelle,

It may seem uncommon to have bipolar disorder in your country, but it may be just under-diagnosed. Maybe because of social stigma.

My sister wasn't surprised when I was diagnosed. Others in the family were, but most of them weren't around to see my behavior as often, and they really had a poor understanding of BPD.
My father is bipolar, but has never been treated for it. He's an alcoholic.

It may be a good thing your doctor was able to hear from your sister and see how you act together. It's likely your sister was trying to help and protect you. You can always go to appointments alone if it's more comfortable for you.

Kay