As a part time English teacher, I have the same problem, even when I'm writing prose. For example, "the person whom you were looking for" doesn't sound quite right, but it is grammatically correct. The song to which I most like to change the words is as follows:

If today WERE not an endless highway, If tonight WERE not an crooked trail, If tomorrow WEREN'T such a long time, Then loneliness would mean nothing to me at all.

However, the following, from the last verse of Paxton's "Marvelous Toy"

" and he loves it just as I"

just doesn't sound right, and I wouldn't write, say, or sing it that way.