The day in the life of a slave during that period of our U.S history was obviously tough beyond imagination.
Slaves worked mostly on plantations and farms 12-15 hours a day against their will from sunrise to sunset. There was no pay given to them in exchange for the work and they were considered less than human by slave owners and many white people who were not slave owners.
They were often whipped, beaten, and degraded for no reason at all other than to keep them from standing up to their "masters". They were sold and traded as property, tearing them away from family.
Slaves experienced different types lives depending on where they were or what type of plantations they were working on. As an example a slaves could be found working in groups or individually.
It was also common for some slaves to have a certain number of tasks to complete in a day before they were allowed to quit or in some cases they simply had to continue to work until their "master" said they were done.
Working conditions were worse than others depending on what type of crops were being grown. Rice plantations were known to have poor working conditions which is why they had different structure for their slaves.
Introduction to U.S. History, 2015, Open Stax Text