I have had perfec attendance at work for 4.5 years and never had any bad marks on my record. I also worked 3rd shift all this time. Beginning of 2013 we were all put on 1st shift. I am a diabetic and some changes can effect my readings.
I was given a 3 day layoff for being accused of sleeping. We were told by a boss to wait while he looked for work for us, I had a headach and closed my eyes. He accused me of sleeping. All of us were sitting doing nothing cause we waited for him to come back with tasks. The second time I was having a diabetic issue of my sugar dropping, I did not get break because we were busy. My lead gave me a piece of candy and told me to go rest for a few minutes. Again accused of sleeping. I was questioned by HR & told to bring in a note from the Dr.
Employment / Labor Attorney
The only way you would potentially have a case is if you have evidence or proof of other non-disabled employees who also slept on the job (or were thought to have slept on the job) and were not fired. Otherwise, if the employer had a good faith belief you were sleeping and was merely mistaken, that would not give rise to a claim. You can file for unemployment insurance and they will have to prove that you were terminated for misconduct connected to your employment but be aware that just because you may receive unemployment benefits does not mean your termination was necessarily 'wrongful.' Best to consult with a local employment attorney but the limited facts you state don't really make out a claim for anything,
Lawsuit / Dispute Attorney
If you have a discrimination theory about retaliatory discharge or hostile workplace conditions you'll need a lawyer. Religious belief, age, gender, race etc. all are discriminatory reasons for which you cannot be legally fired and upon which you might base a wrongful termination suit.
If you are an at-will employee, you can be fired for any reason or no reason, except unlawful discrimination. If you do not have an employment contract or union to represent you, your recourse is limited. Discrimination based on age, gender, race, religious beliefs etc.... may give rise to a different answer.