Carrie! I don't know what your disability is but if you would go on the usa.opm web site their is some information on hiring adults with disabilities.
You can apply for the schedule A handicapped appointment this appointment is to hire a person with a physical disability or mental for two years and then convert to a permanet position. You have to have a certification from your State Voc Rehalb telling what you can do. I don't know what state you're in but, I am in SC and have had no luck so I am wishing you good luck because you may be in a state that is not behind like SC.