I don't really have any advice but did want to let you know it doesn't always take years. I was approved in 11 weeks for SSDI.

I don't understand though how waiting for SSDI is preventing you from going to school and having a stable income/job? Usually if you need SSDI you don't have a job or you work only a small number of hours. If you are able to work SSDI is not going to help; you have to be completely unable to work to be approved. I'm not sure I understood you though so please correct me if I misunderstood.