Why is my text messaging typing huge letters?

[AC Question]

I've tried adjusting it using my volume key but all that does is lower my volume or raise my volume. If I lower my volume I can't hear when someone calls me to talk. It doesn't adjust my font size. I've gone into settings and set my font to small but my messaging text is still huge. I can't seem to fix it. I've read several messages on fixing it and they all say to use the volume key but I guess I'm not doing that correctly. I'm still trying to learn how to use my Galaxy 5s.

 

[B. Diddy]

Welcome to Android Central! Look at this video:

https://www.youtube.com/watch?v=0D-sQJLNK2M