[Momaru]

Glad to hear you're ok man. Sorry about the bike, but would've been worse if you'd have gone headlong into the wall, so good call to try and stop

+1 to more front, less rear. It just takes practice. Sounds like you were trying to get some in that garage and just wound up getting some fairly expensive experience.

Jamesio, I believe the term highside doesn't necessarily mean going over the handlebars (like you did a stoppie and failed to hold on, which is called an 'endo') so much as it is exactly what seems to have happened here. The terms refer to the side of the bike you are exiting from.
When turning, you're leaned. Dropping the bike the shorter distance, into the turn (through loss of traction, etc) is a lowside. Typically the bike hits before the rider in a lowside.
Conversely, having the bike kick up and go over towards the outside of the turn, falling on the side that had been facing more 'up' is a highside, usually by way of the bike standing upright too fast due to locking the rear then releasing.