Mate that feeling of not being able to stop thinking about it is honestly one of the most consistent things I hear in abduction accounts. Like the sighting itself is one thing but its the mental loop afterwards that gets people.
What was the light situation - was it lit up or more of a dark shape against the sky? And did it make any sound at all? Those two details tend to narrow things down a lot faster than anything else.
I'm in Cornwall and had something similar a few years back over the fields near my house. Never fully explained it. Still think about it sometimes so yeah, I get where you're at. Definitely post more details when you can.