Polly knows of what she speaks!!
I've had Bipolar disorder since i was 13 - not diagnosed until I was 30. I had very few friends but only because I was very depressed and missed alot of school with stomach problems (more like it was schoolphobia since I was undiagnosed and couldn't handle the stress of school without the right meds)
KNOWING that something was wrong with me, that I wasn't like the rest of the kids, set me apart in my own mind. Instant low self-esteem since "belonging is the #1 thing in school, right?
If possible see if you can find an interest or a talent that you can encourage. Many bipolars are very creative - artistically, writing, photography etc. See if you can get her into an extra club or class or summer seminar on something she enjoys and can excel at (apart from her friends...)
At the very least find ANYthing to praise her for. Even though they had no clue what was wrong with me my parents never left any doubt in my mind that I was loved, supported, unconditionally safe...
I think that that solid foundation (they got all us kids to church all thru school also) made a BIG difference in how I turned out as an adult.
Stabilized on lithium for 20 years, able to work at a job, married to a wonderful man for 15 years.
I don't think my parents would have believed that my life would have turned out this way if you had asked them while I was catatonic or bouncing off the walls!!!
Come back anytime for support. There are many people who check in here who have children your daughter's age w/Bipolar Disorder...