I'm not gonna comment on your physical injuries because I haven't been in your shoes, and I imagine from reading your post that you went through alot with your backpain. You can use determination as one of your 'skills' or 'assets' in an interview.
Job wise...
Don't sweat it. I know people who haven't worked 4 jobs their whole lives. And unless it's a trade, no one remembers anything they learn in school. School is basically a good way to show employers you are knowledgable on the subject, and had the drive to finish. The real things you will carry away with you the rest of your life will be picked up with work experience.
Land an entry level job in accounting, and start working. Before you know it, your previous 4 jobs will be irrelevant (I think so, don't think you've mentioned what they were), and you can use the current job to move on up the ladder.
Lastly, as mentioned, the job market is hard right now, took me 4 months to find a job. I got discouraged, felt like crap, but you gotta remember for every position you are applying for, 500 other people are aswell. Keep at it and don't take it personal.
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