Right so this is exactly the kind of thing that keeps me up at night - not in a scared way, more like that electric feeling where your brain just won't let it go. I know that feeling you're describing.
Living near Glastonbury I've had a couple of moments like this and the thing that always gets me is how the memory stays so vivid. Like your brain knows it witnessed something it doesn't have a category for yet.
Can you describe the shape? And was there any sound at all, even subtle - like a hum or that weird pressure feeling some people report? Also what time roughly, because there's been a few other reports around the UK lately from what I've been reading.
Don't let anyone brush this off until you've had a chance to really walk through the details. The early account before you've talked yourself into or out of anything is genuinely the most valuable bit.