Your focus is probably shifting because you have AI Servo on. That is for tracking objects. You can switch to AI Focus or just the regular focus. Its in the manual. You can change focus types by pressing the mf function button on the top of the camera. The mf function button will only change modes after you press the focus select on the back top right of the camera. Also in the manual.
Thankyou so much!!!!
I was in the actually menu checking and unchecking the focus options. What I didnt realize was, what I checked and unchecked wasn't what the camera used, it was just the options the camera had when choosing focus options(by clicking mf function button) so now I know, they way to change how the camera actually focuses is to use the mf function button lol...