Am I entitled to receive overtime?

First, you are likely non-exempt as a desk clerk. Second, your total hours indicate you likely worked more than 40 in a week, putting you into...

Does signing the At-will employment means that I am employed?

1) Yes. You likely are a shareholder. You own shares in the company, but not the company itself. The company may be, e.g., a subchapter "S"...

Legal Issues: 1) Contract for repayment of training already provided enforceable? and 2) 18 months term enforceable? Your training was...