Can I file for ssi/disability if I have really bad copd?

Perhaps... It would depend on your job as well as how the disease is affecting you functionally. Only your doctor can answer this question for you so see your doctor who can advise you on this issue.
Yes. After clinical evaluation, with regard to copd, an fev1 of less than 1l is a qualifying factor for disability. Severe shortness of breath, recurrent hospitalizations, and oxygen need are also considered.