Right so first thing - what colour was it? That's always the detail that gets overlooked in these early reports but it tells you a lot. Hovering behaviour over water is actually really well documented, there's a whole category of UAP/cryptid encounters centred around lakes and reservoirs and I've been tracking Welsh cases for about 15 years now, got a decent database going.
The other thing I'd want to know is whether there was any sound, or more specifically whether the absence of sound struck you as unusual. A lot of witnesses describe this uncanny quiet around the object which is worth noting down if you experienced it.
Don't let the memory go stale, write everything down tonight while its fresh, even the stuff that seems irrelevant like what the air smelled like or whether animals were behaving oddly. You'd be amazed how much that contextual detail matters when you're trying to build a proper picture of what happened.
Where in the country are you roughly? No need to be specific, just curious whether this is near any sites I might already have on record.