I'm going to take a sick day at work tomorrow.
Why do you feel like you need to take a sick day?
I feel like I need a break because I feel drained.
I'm sure you feel like you need a break but you should only call in sick when you're actually sick. Your work depends on you being there and you should not abuse your sick leave. Schedule a vacation day if you need time off.
I really just feel like i need this day off.
You should really save your sick days for days when you are sick. If you run out, you may be forced to go to work sick which could get other people sick as well.