But Blindsight is a third level spell, that was released specifically in the forgotten realms rulebooks (both Magic of Faerun and Player's Guide to Faerun). It is specifically canon to the world we play in. It lasts turns per level, not rounds.
Unlike True Seeing, it's supposed to nullify normal stealth (although your identity may still remain concealed in some cases, people will know someone/something is there with blindsight). You can read about it here. http://www.d20srd.org/srd/specialAbilities.htm
So don't worry, be happy!
