Have everything turned up to max.
Did one of the training missions.
Moved on to the mission with drones that attack.
My speed became around double the norm.
Very hard to hit one of those buggers when everything goes double speed. Had to boost away a few times then turn around when it was at 1500 to laser him as he came at me... restarted the game and it so far hasn't returned. I miss strafing from descent/X... and it seems auto aim from X has also been a spoiler.

The game has time compression, meaning that it is possible to turn up the speed of the game significantly while playing if you hit the right buttons by mistake. I can't recall wich buttons though. You better go through the control config and check what the combinations are for turning it back down if the problem persists.

Yeah, that would be a good thing to find out.
*boring escort missions*

By default, Shift+> speeds up, Shift+< slows back down. There's a number in the bottom right corner of the HUD that tells you what time compression you're at.

Alternatively, if you feel sure you'll never ever need this, delete the key mappings for it. I did the same after almost dying at the end of a very long mission (last mission of Silent Threat IIRC), accidentally hitting one of the buttons that changed the view and not managing to get back to my cockpit...
If you do, you can also remove the indicator from your screen if you feel like it; if you can't control time compression there's no reason to have an indicator for the current value (as far as I've seen all missions start at x1).