Birth control pills and Ella

my doctor told me I'd be fine using Ella and my pills at the same time.. I just found out they cancel eachother out kinda or they just make the other not work. Also you're supposed to stop taking the pill for 6 days so they don't fight eachother and I didn't know til after...... has anyone gotten pregnant from taking both? because I'm always on time taking my pill... but I took Ella and that's really stressed me out.. I'm supposed to get my period today but I'm hoping this helps calms my nerves before I get it if I do 😐