My question involves labor and employment law for the state of:
Missouri.

I work for Walmart as a Cart pusher (official title "stockman"). My schedule has always been erratic, but is consistently an average of 4 8 hour work days a week.

Walmart's work week starts on Friday. I'm currently scheduled to work full 8 hour shifts for the next 6 days in a row, and I'm not sure if I'll be getting overtime, or if I can refuse without risking my job.

So my questions are:
1. Can an employer force overtime, and if I refuse, can they legally fire me for that?

If one is yes:

2.Can an employer legally manipulate your schedule so that you work more than 40 hours in a 7 day period with no overtime pay, but "technically" not overtime because of when their work week starts?

Here's an illustration of my schedule to help a bit:
Friday: Work
Saturday: Off
Sunday: Work
Monday: Off
Tuesday: Off
Wednesday: Work
Thursday: Work
Friday: Work
Saturday: Work
Sunday: Work
Monday: Work
Tuesday: Off
Wednesday: Off
Thursday: Off
Friday: Work

Where you see the word "work", that means a full 8 hour shift, and "off" means I don't work that day.


Also, as for my username, I didn't want something that would be affiliated with my accounts on other websites.

Thanks in advance for any help you can give me.