why did my record player slow down, speed up, then go back to normal?

Occam's Razor: the simplest answer is always space aliens.

And you think that's all it is then. Interesting.
https://www.youtube.com/watch?v=G554Xa8MElg

ET phone home.

Now after a full day of denial the military has released evidence of multiple sightings by pilots and radar. What was originally denied to even be happening is now openly discussed as being due to space aliens. Unfortunately too late, as we can see from the lack of replies the OP has been abducted. If only he had known to unleash the yodeling. https://youtu.be/aTe0MjAZvMU?t=49

Space aliens. Without more details it is hard to say from what planet.