I agree, it is not an automatic approval for SSDI but, your chances are better having qualified for Medicaid.
You need to apply for SSDI (SSI) same process with the exception that once you file the SSDI application you will need to qualify financially for SSI.
I recommend that you get all medical records, complete a paper application and go to your SSA office to apply. Online applications do not include medical evidence or any supporting documentation.
Good luck.
Trudi