Is there a way to invert the y-axis for the controls? I'm using mouse and keyboard, if that makes a difference.

Not in-game.

If you have a gaming mouse, or another mouse that comes with a control panel or similar software, you can try doing it there. However, this will likely change the axis everywhere in the game. There are possible workarounds using third party software that would create a shortcut to reverse/unreverse the axis.

However, I think a much better solution would be to simply get used to it. It was weird for me for a day or 2, but then it becomes natural and you stop thinking about it.