don't feel so lonely, cause you're not!!!
the one thing about bipolar is that is does strip you down on the inside and you are no longer know who you are. and you do become a different person.
the beautiful thing about this is that you can fill yourself up with whatever you want! the things that bipolars tend to learn most about are compassion, empathy, beauty, appreciation. and these are wonderful things. just try to nurture your new qualities and see where it takes you!
maybe an open, honest conversation with your family about these types of things would go far. people aren't used to others being so frank, but i think they tend to like it. we hold in our feelings and emotions so much!
i would recommend a journal. you can think through things before approaching your family as well as figuring yourself out.
don't know your situation, but if you still are not stable, do not give up. it takes a lot of strength and endurance. but, whoever is above gave you this challenge because he knew you could handle it.