There are attorneys that specialize in facilitating clients' application for SSDI, and you don't even need to pay anything up front; they garnish their fees from the first few months of your benefits, which makes their compensation contingent upon your approval. Try Googling 'Social Security Disability Attorney' for your area. You can at least talk to one and get a nuanced opinion of what your chances are for being approved for SSDI, or what you might need to do in order to help your chances.