Windows – Uncontrollable scrolling

This started happening about an hour ago. I didn't install anything new, didn't restart the computer, basically did nothing. I noticed this first when I tried to use an online 3D human simulation. It was constantly zooming out. I'd zoom in, it would fight me, and after I stopped, it would continue to zoom out. I closed the tab, slightly annoyed by the bad simulation.
A bit after I opened Google spreadsheet and as I opened the tab, it would simply scroll to the left (not changing the cell selection). I don't know if I should call that scrolling, since it is basically jumping about three columns at a time. Also, it doesn't happen when the mouse isn't hovering the actual spreadsheet but is positioned elsewhere.
Next weird thing – as I open the start menu (Windows 10), the area where the mouse is hovering is scrolling down (not smooth either). This is happening with webpages only from left to right.
Also, when I'm scrolling a webpage with my mouse, it is very laggy, as if it is fighting with other input.
I disabled my mouse – it changed nothing. I disable both my mouse and my touchpad, again – nothing. As long as the mouse is hovering a scrollable area, it's scrollin' and I'm hatin'. Help?