I had a song in my head. It was the epic, fast-paced violin song...
...That happens to fit perfectly with the tune of THE tune, which I'm pretty much positive at this point is my creation (or, at this point, might as well be; I've definitely made it my own, at the least).
The annoyance comes in, because in this particular case...I'm not sure whether it was another of my own creations, an epic variation of THE tune, or if it was just an already-existing tune that just so happens to coincidentally match the timing and many of the notes (the string version that was playing of course having like 3-4 times as many) being the same. This has happened with songs before, so it's possible.
And that bugs me, not knowing. Especially since I could only get a small fraction of the tune to play through my head.
...The second part, which is where the not sure part comes in, is that I promptly forgot what the tune was while taking a shower. I had it in my head, as I woke up. But some time during the shower, I lost it. And when I tried to regain it, I ended up getting Trans-Siberian Orchestra music stuck in my head, and it's still playing.
...Mind you, that's certainly not a bad thing. I love their music, so having it stuck in my head is nothing but good. It's just, I'm absolutely 100% positive that it WASN'T their song(s) in my head before, so I know that whatever tune I had, it isn't what I have in my head right now.
Thus, the annoyance.