I work in Texas and I am scheduled to work 45 hours per week but I actually work even more than that. I have no real lunch break - I can grab a bite here and there but I don't get to sit down and have any time to myself - I do have 2 days off during a 7 day period. Anyway, how do I know if I am an exepmt/non-exempt employee - I am on a bi-monthly salary (paid 1st & 15th) but I was never told or signed anything that said I wouldn't be paid for working more than 40 hours - is it based on personal income? Please explain. Thank you.

It all depends on your job duties as to whether you qualify for exempt status. You can start here. If you have questions after reading this info, please post back.
http://www.dol.gov/esa/regs/compliance/whd/fairpay/fs17a_overview.htm