is sleep apnea considered a disability

I was terminated from my job as a mechanic w/ a public school system because of tardies. I informed the business manager that what has been happening is, I start eating breakfast and I wake up after an hour to 3 hrs and realize I passed out. I told him I thought it might be my diabetes, he told me to go to the dr and get checked over. When I went the dr told me after doing a hb1ac blood test my diabetes was fine and it sounds like my apnea. An overnight sleep study was ordered. The results showed I had moderate to severe apnea, i never considered that as I had my throat widened and a septoplasty done and thought I was fine. I started on the new cpap prescribed to me. The time I was terminated my mask was off when I awoke, as was it the 3. Times before. This has to be considered a disability. Is it??