Afraid to drink the tea...

so i want to start the cleanse officially tomorrow and heard I should drink a cup of tea tonite, the night before and then one in the morning and one at night. Im afriad of how its going to affect my stomach, if im gonna be awaking during the night to use the bathroom or be running all day tomorrow. I have a big day ahead of me (working at my new job, meeting an employee of mine or 2) so i dont want to have to run, but I know if I dont try it I wont know how it effects me..I actually want/need it to do its job but I dont know what to expect, so i guess im just a bit nerved ....