I'm multiply disabled. My SSI/SSDI was originally approved for my mental illness, but since then I've also been diagnosed with ulcerative colitis, enteropathic arthritis, and severe chronic fatigue/weakness that causes mobility impairments. I feel worthless a lot...but not all the time.
For me, the biggest help is identifying that my sense of worthlessness comes from outside sources. I came from a family that only valued people for their achievements, and that had a profound effect on my view of myself. Also, a lot of it comes from the societal rhetoric that disabled people are lazy burdens on society who just choose not to work and force others to support them. I've internalized so much of that, but being able to recognize it as something separate from who I actually am and being able to name it as ableist BS does help.