Can I apply for SSI while being enrolled in vocational rehabilition?

I get Nonoccupational disability from my state as I was employed with them for the last 8 years and paid federal tax which apparently excludes social security.

I am enrolled in vocational rehabilitation but am currently not looking for paid work. Just as a job shadow finding out limitations and gathering skills to be hireable in a job I can preform and excel in. Thus I haven’t applied for unemployment pay. Vocational rehabilitation says they are willing to fill out forms listing me as incapable of working at all. But I almost equate that to a death sentence.

I only receive 463 dollars a month for disability. And the only other aid i receive at present is $250 for food a month.

I was denied by SSI saying that I hadn’t proved I am incapable of working. I don’t want to quit vocational rehabilitation so I don’t want to prove I can’t work.

Non occupational disability evaluated me to be incapable of performing physically at my jobs. And all of my past work experience was physical.

But there is no way I can survive on 463 a month. Right now I am unhireable in work that i could possibly do. Although i really havent tested my limits. There is great fluctuation day to day and of i over do it then i start tail spinning downward. So I am trying to build my strength and tolerance while not exerting too much stress.

So where is the middle ground in funding. I just need some time to get on my feet. But as far as aide there is seemingly no place i can turn without perpetuating a lie.