I created a new iTunes library and now cannot find the original one, which has a thousand albums on it! What happened?

I created a new iTunes library to put speciald songs into, using the instructions on the Help section of iTunes. NOW - I cannot locate my original iTunes library, which has a zillion tunes on it! When I open iTunes to "select a library" the only choise I am given is th one I just created, which only has one album on it. What happened to the original iTunes that I just got the way I wanted it, with millions of tunes on it??????