How do you stop the Numbers autofill?

God I hate how simply difficult apple is. HOW DO YOU STOP THE ******* AUTOFILL????????

I am trying to fill in cell text in a numbers sheet. I want to create a cell text for every month however I would like it to read

JAN, FEB, MAR, ETC.

Stupid apple INSIST on autofilling the ENTIRE WORD... January February etc..

I DO NOT WANT THIS. I WOULD LIKE TO FILL IN MY OWN **** TEXT WITHOUT IT CHANGING. SO FRUSTRATING

PLEASE HELP! I know it seems ridiculous but I can't figure it out

[Re-Titled by Moderator]