To the OP:

IMHO you've done nothing wrong. If you read back the wrong taxiway, it was the tower's job to correct you. Separation with traffic landing behind you is not your problem. If I had to guess, the tower was hoping you'd get off the runway sooner than you did, and maybe he/she had to go plan B, and maybe even send someone around. It still isn't your problem.

File a NASA form. Don't lose sleep!