Sorry you're feeling so bad right now, Elizabeth. It sounds like you feel overwhelmed.
You said your Bipolar Disorder is out of control. Are there things you can do to take control of it? Are you prescribed meds, and are you taking them as prescribed? Have you made, or can you make, an appointment with a psychiatrist for an evaluation or medication adjustment? Are you engaged in, or have you researched, any complementary therapies (group therapy, CBT, etc.)? Have you read the self-help literature that's out there for people who have Bipolar Disorder? Making a plan for getting the Bipolar Disorder back under control might be one way to get your feet back on solid ground. Even if it's not perfect or 100% successful, you'll have something to work from, and towards.
Why do you think you're a burden to your family? Have they said that? If they have, is that true or how things must always be?
Even if you don't have any friends IRL right now, that doesn't mean you'll never have any. And you've got friends on here (hi!).
You've obviously got a strong will (weight loss and no cutting for several years!); you can get through this. Hang in there.