I am a machinist,programer I am a salary employee I work over 40 hours a week and have to punch a time clock w?

Thy make me punch a time clock when other salary people don`t.Thy say i am exempted from overtime.I work a eight and one half to nine houri day five days a week.I cant take a lunch break or can I take any breaks.I work Straight Thur.Over 40 hours a week.Thy made me sign some papers a long time ago.Thy did not tell me what I was singeing,I trusted them I have been with the company for 12 years.What should I do?