Any other Mentally Normal peeps have trouble with CONSTANT FUCKING MUSIC in their heads? It Never. Bloody. Stops. All. Fucking. Day. It's double fucking speed Que Sera Sera at the moment, the same two lines, round and round and round and round and round and it's like being in a Hitchcockian depiction of SLOW DESCENT INTO SODDING MADNESS. If I'm lucky I get two tunes at the same time or two that rotate from one to the other and back again in a constant thirty second loop. Sometimes I can stop it with actual music but if I'm unlucky my brain finds one of my mental musical obsessions to sing along in harmony/cacophony with it. It goes round and round and round and round and round. I was singing "I'm walking on sunshine, whoa oh, I'm walking on sunshine, whoa oh a, I'm walking on sunshine, whoahohohaa, and don't it feel GOOD - do... Do doodle oodle Ooh ooh ooh ooh oh ooh dum dum doo, do doodle oodle ooh oh OOOH", and repeat x1000, for so bloody long earlier, and actually most of this week, and it just wouldn't exorcise itself. Stupid sodding brain. I think I might be damaging my ears listening to music loud enough to distract myself 
I once several years ago developed such a pachelbel's canon mental habit I started literally hearing it, like it was playing quietly in another room. Ye. Fucking. Gods. I used to like that tune once upon a time, but months of having it in your head on constant fucking repeat really plays out a piece.