Are you sure it’s “only”? Because Ctrl+ScrollWheel is the zoom feature, as Ctrl+NumPadPlus Ctrl+NumPadMinus (fixed: you said it went tiny, not huge, which is zooming out). And if you have a laptop with a trackpad, holding down Ctrl and then sliding on the trackpad might also trigger the zoom behavior (and some might be sensitive enough that you don’t even have to be fully on the trackpad, it might sense you hovering a couple millimeters above)
Or have you hit Ctrl enough times that Windows is turning on its Sticky Keys feature, because Sticky Keys can make things behave differently than you are expecting.