Take that song, put a LOT more random words and sentences and conversations in it, and speed it up about 5x and you've got my racing thoughts.

I tend to end up thinking about a million different conversations with myself all at once. The funny part is that I will skip between them and then go back to where I was and keep going and then back to another one and keep going - almost always with a lot of backtracking, and sometimes I won't make it past the initial few thoughts and then keep repeating them (especially if it's something I WANT to be thinking about further, I simply won't). Usually I'll be singing songs in my head and having images flash around and will think about a lot of memories and be beating myself up over anything that's not making me feel good and arguing with myself and telling myself off for arguing with myself and not making any decisions but making a lot of choices that I'd like to decide were my decisions and then forgetting them and then plannning to write them down and then forgetting what i was going to try to remember and then realizing that I have no idea what other people were actually just talking about because I was off in lalaland and then I will try to say something to them and then forget what it was half way through the sentence because I'm already about ten sentences ahead in the conversation even though they haven't a clue what I'm on about etc etc.

Sorta like that, but less organized. And more argumentative. And not sequential.