Yes, that solve it...thanks so much for posting.
More information:
The problem occurs (at least for me) via the less-than-helpful shortcut "ctrl + scroll", when reading/composing an e-mail- this is what made the text so small in the first place (inadvertently pressing ctrl while scrolling).
In order to "fix" it, as the helpful post mentions, you need to open an existing e-mail in a separate window...not the reading pane nor a new/compose pane (double-clicking an email in the list does it for me). Then you will have the "Zoom" button in the ribbon, which allows you to reset to 100%.
Or, I suppose, you could also hold down "ctrl" again and scroll with the mouse/trackpad up/down to change the Zoom back...but after getting burned I personally don't want to touch that again!
(Microsoft- there are so many UI issues going on here; I would suggest someone take a look this whole process!)