I agree, as much as you may love your sister you cannot put your relationship with her in front of your own health.
On a different note if you are interested in meeting people who have the same or similar issues as you check out No Longer Lonely : Online Social Community for Adults with MentalIllness it's a website for people with mental illnesses. I met my wife on in 12 years ago and still going strong!
I hope you get the support you need.