Amos: You're right, listening closely I hear the line is "But if this ever-changing world in which we're livin' / Makes you..."
That makes more sense than with three in's, one clearly redundant; someone pointed it out to me the other way, and I stupidly took it on faith. Memorable music, but the lyrics always seemed tossed-off, another melange of half-songs. The phrase "in which we're livin'" still sticks out as a silly tautology: where else would we be living?

Betsy: It could be "in which we live" or "we live in" (with a dangling preposition), but "in which we live in" is clearly improper: one would not say "We live in in the world".