I pushed a magic button and now my cursor (the blinking thing that shows where you type) split itself and now Eclipse is acting like a plain text editor/like Microsoft Word. The cursor, which usually looks like "|", now looks like "¦" (what Wikipedia calls a 'broken bar' or a 'parted rule' rather than a normal 'vertical bar').
I just want to know how to get Eclipse to act normal again, and what I accidentally did so I don't do it again.
It sounds like you have accidentally switched from Smart Insert mode to Insert mode.
Press Ctrl + Shift + Insert or tick Smart Insert Mode on the Edit menu to switch back.
Smart Insert is the feature that automatically insert closing quotes and brackets when you type the opener and places semi-colons at the end of the line when you press semi-colon (if you have the preference for that enabled.)