I don't think you need worry about this. There are all kinds of little-known sleep disorders like this one. I've suffered from several of them all my life, though I find they're fading now as I get old. All of them are at their height when you're in your teens and 20s.
My particular one was waking up as two people - particularly if I woke suddenly in the middle of a deep sleep, to go to the toilet for instance. I'd feel very resentful that "she" had woken "us both" up, and I would hear my own voice in my head, grumbling about it. This would continue throughout the time it took me to get to the toilet and back. One winter night, I peeped round the curtain on the way back from the toilet, saw deep snow and started wondering whether I'd wear my green or my red hat the next morning. The angry voice in my head exploded: "Now she's talking about b****y hats when all we need is to get back to sleep!" I laughed about that when I remembered it in the morning.
I also used to wake, even in the morning, hearing very loud music in my head. Another one - which I still have to this day, though less often - is visual hallucinations on waking. Sometimes household items, often miniaturised, but more often geometric patterns all over everything. It takes several minutes for these to fade. Like you, I can get up, walk into the kitchen or bathroom, and still see the patterns or hear the music for several minutes.
These phenomena, normally down to minor glitches in the temporal lobes of the brain, are actually quite common, but most doctors don't seem to know much about them. There's no reason why they should, really, as they're not very significant and aren't a sign of mental illness. The reason we don't hear more about them is that people don't normally discuss them for fear of being thought crazy.
I find them very interesting, though there are others I experience that are much more scary, so I won't describe them here. All this started when I was about 5, stopped when I got into my teens, then came back with a vengeance in my early 20s. I'm 71 now, in perfect health and have never had any mental illness, except for minor depression in my mid-20s.
Probably best not to share with your doctor. He/she is most likely to assume you're making it up, but might just be tempted to prescribe anti-depressants or something, that won't help at all.Just enjoy being a bit different!