You can do it online and work on the side. Do a google search for "Online GED program" and I'm sure something will turn up that you can do. That would allow you to do the work for your diploma and still be able to have a job to support yourself. It'll be tough - they will be fairly demanding on the deadlines for submitting your work but it'll be well-worth it in the end.

 

Maybe some kind of independant study program would work.. I took the Califonia High School Proficiency Exam and got out of my highschool 2 years early