Keyboard resizing and is throwing off the calibration

[chargett]

I am a brand new user to the Andriod phone and the Samsung s5 (like two days now). When I'm typing a text message or a comment in Facebook, if I type too fast the screen display will enlarge making everything larger than it needs to be. It acts like I've asked it to zoom in. I am not able to figure out how to make it zoom back out, or make it go back to it's normal size. When it does this zoom in thing, it takes the letters and # out of alignment (if that makes sense) which makes it impossible to continue to type the message. For example, when I type a letter like G, it will display T or R. Or if I hit the back (X ) button, it will display N.

What am I doing wrong...and how do I it? Thank you in advance for your help!!!!!!!