Email Composition - I goofed and can't find an answer!

 I just typed and sent an email.  As I was doing it I must have accidentally touched a key or something. Now when I send an email the text doesn't fill the page. It's about half as wide as it normally is. (it looks normal when composing the email, but narrowed after being sent)

I've tried different things with the keys, and looked for answers here on the forum, but at this point I'm stumped.  (picture this but narrowed to about half, with a blank area to the right of the text)

I know it's something simple...I was using an Alt Code and it happened after adding a symbol. But nothing I try seems to switch it back to the way it was originally.

Any help is greatly appreciated. I know it's a simple fix but I can't find the fix! How do you get the text to FILL the page?