I've thought about this a lot because, well, my brothers are from my future, right? And I have nieces and nephews from a future that doesn't involve me, right? So even though I'm here, and I'm very much not dead, that hasn't changed their pasts. They don't suddenly have memories of me being there for weddings and birthdays. I'm still gone because it's not actual time travel.
If I'd used a time turner to travel to New York 2019, there would be rules that I would need to follow, but Georgie and the others would be 21 years older than I last saw them, and they're not. So those rules don't apply.
Maybe don't talk to yourself if you meet a future you because you might go mad, but I don't think you can affect the future in any way.
And I think this feels weird because you don't have what you're used to having. I would feel the same way if my wand and magic suddenly stopped working, but that's also physically part of me, so it would be like Georgie's ear, right? An actual body part missing. So this is kind of like the plugs our dad collects: something to look at but that doesn't actually work in a magical home.