It's okay

We all make mistakes!
Unfortunately, I don't have TS1 currently installed, so I can't tell you how to put it in windowed mode or anything, but I just did a search on google and found
this thread at TSR which tells you how to put the game in windowed mode. If you do this, the game won't take over the entire mode so then you can play your music in the background

Oh, and I'm sorry about your cat. Sometimes things like that just happen :/