I just started experimenting with the alignment tools, and I must have done something weird because now I can't move objects freely anymore. Instead, the object sort of "auto-aligns" and a message pops up by the object rotation center that says "object rotation center to object rotation center". I don't know what this means. I tried resetting my preferences to default, but it didn't help...

Hello there,

You may thicked in the threat selection as a group option or
even changed the alignment from the "last selected" option in the dropdown menu at the top of the panel.