No one can tell you if that has happened. But if you try to e-file and your e-file gets rejected for a duplicate SSN already in the system that will be a clue that some one may have claimed you as a dependent. Even the IRS will not tell you who it was if that happens. If you cannot be claimed as someone else's dependent and cannot e-file, then print, sign and mail your return. The IRS will process your return and sort out if someone else claimed you.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**