Hi kzaug.
Not strange at all, rather normal I would say
Many people could describe similar things here I'm pretty certain, myself included. It's basically related to how our brain/mind/memories work. When you listen to those old tunes that you encountered much earlier in your life, probably in the contexts that you remembered suddenly today (partying etc), it triggers the recall of those old emotional memories. They may have nothing to do with your current lifestyle, wishes, goals, values -- simply just memories and old emotions resurfacing. It's a very important phenomenon in relation to addiction recovery and relapse prevention in early sobriety because these memories can initiate urges out of the blue.
You can read about it online if you search for things like "cue addiction" or "cue reactivity". Here's wiki about it:
Cue reactivity - Wikipedia, the free encyclopedia
Usually it is suggested that it's best to avoid these cues or triggers in early recovery. I heard many people say, and experienced it first hand, that it's hard to listen to old songs or watch films etc that serve as such reminders. The nostalgia might be pleasant on some level, but in people like us with addictions (similar in relation to old traumatic experiences) it comes with this "side effect". If you find it disturbing, perhaps better to avoid listening to those things for a while as the safest approach around it.
Glad to hear you are doing well otherwise, keep it up