I applied for disability in Feb 2000 and was approved after about six months. Yes I felt guilty and a big part of that was because some of my family and friends were telling me to pull myself up by my bootstraps and get back to work. They told me I didn't need all those medications and I should fire my doctor. I didn't "look" sick.
I was unsure. I thought maybe my psychiatrist had exaggerated my mental illness to "help me out" so I wouldn't have to work. I wasn't sure if I even had bipolar though I knew I had PTSD. It was not until I was in an outpatient therapy group in 2006 that I accepted that I really was bipolar and I really was disabled.
Things change. Sometimes they get better and sometimes they get worse. Nobody has a crystal ball. I hope that I can go back to work at least part time at some point.
Try to accept that you have a right to disability now and perhaps at some point you will no longer need it but it is there while you do.