Can An employer cut your wages without demoting you? Also can a small business owner make you work ten hours without a break?

I am the manager of a store. The owner cut my pay by two dollars an hour right after my divorce. He never demoted me though. Now right before christmas he has cut me 11 hours a week. I'm having a very hard time finding another job. The owner here will not allow me to get a second job. We had an argeement when I came to work here that I could not work Saturdays. Now he says if I do not work Saturdays he will fire me and I will not draw unemployeement. I can't work it though cause I have no one to watch my kids. Every Saturday you work though you work a 10 hour day with no 15 min. breaks. Sometimes he does not even allow you to sit down at all!