Would I still be able to qualify if I don’t have a diagnosis for my disability?

To make a long story short: I(recently turned 18m) have debilitating paresthesia/nerve pain that has completely squashed any possibility of me being able to work or live a normal life. My family has always been rather impoverished, and I was on survivors benefits for several years for a parental death until I aged out.
For a little while, I worked for a few months and tried to push through it but I just couldn’t handle it physically, even with accommodations, so I unfortunately had no choice but to resign from my job.

The thing is that I have no diagnosis, even though I have done many tests and have been struggling with it for a long time. My doctors have no idea what is causing it. I have been in physical therapy for months as well. I’m trying to think of a future for myself but I will never be able to work like this, even on medication.

What if I never get diagnosed with something? It’s looking like I won’t at this point. What do I do in the meantime anyway? In the kind of likely case that I never get a real diagnosis: would I still qualify? I’m sorry if these questions are redundant and this is a bummer of a post. I’m just very young, very miserable with my newfound life of disability, and I do not know where to start at all. I feel so lost