8 buttons from 4 buttons and a potentiometer

[PerryBebbington]

As I see it your problems are:

• Trying to have 8 buttons using an unconventional method without first learning to read one button correctly.
• Reading the state of a button and using that in your code, you should be reading when a button becomes pressed, not, as you are doing, reading when a button is pressed.
• Slowing the code to a crawl with multiple delays.

There are lots of tutorials on how to read a button, here is mine, but there are plenty more:

Buttons and other electro-mechanical inputs (introduction)

Part 2 Part 1 shows how to read a single button. This part explains the code and circuit. Debouncing You have probably heard of debouncing and are perhaps wondering what it is and why it is needed. The oscilloscope trace below was taken from a single button wired as in part 1. The trace shows high and low transitions - some lasting over 4ms - before the signal settles at low. This is caused by mechanical bouncing of the button's contacts. We can use software to remove these unwanted transiti…

There are also lots of topics about problems with buttons, many of which cover problems similar to yours.