Don't know if this will help, WW, but I had called a psychologist friend before making this post:

Jackie
(enthusiast)
Fri Jun 30 14:43:38 2000
24.4.252.105
Re: Old fashioned pronouns

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Tsuwm--
>>and ever since I've had one of the songs stuck in my head (is there a word for that?) <<

Yes, it's a form of obsession, or obsessive thinking:
perseverance of thought. (That's per-SEV-er-ance, not
per-se-VER-ance).

http://wordsmith.org/board/showthreaded.pl?Cat=&Board=words&Number=2319