Or it could be "The Mother"'s mom died before their wedding (Ted & "The Mother"). Or refused to come to the wedding.
I dunno, but the way Ted broke down and cried immediately, and the Mother quickly changed the topic kinda implied it was more personal to Ted than her. Either his mother died, or the Mother was going to die before the kid's wedding. Or Ted, i suppose, but not quite as clean to the lines.
Not to say continuity is perfect or anything, but haven't there been a couple of episodes with flashes of OLD Ted, Marshall, Lily, etc? Can't remember the episode, but there were together on a porch for at least one bit I recall. Thought they all appear older than Ted does in the most recent viewings with the Mother. Of course she didn't appear, as it was before this season. If you assume that's not being written over, more credence towards Ted being ok, and the Mother dying...