International Spacestation flyover

[Fazerider]

Ditto! Pretty funky, mad, never seen it flyby before.

So how come it started off really bright in the West, but as it went over to the East, it just faded away and seemingly disappeared mid way over?!

Yes, it went into the shadow of the earth.
The moon will be doing the same later (unfortunately after it's set from the UK's point of view, those in the Americas will get the show this time).