First Pill

So today I took my first morning after pill and in my head I got over the constant worrying of what to do with myself as the condom broke last time me and my so were having sex. 
Long story short, I took the pill in a 24hour time frame and I did plenty of research on the pill in general. There were plenty of sites and even the pharmacist said that I may experience some weird effects after taking it. Such as nausea, vomiting, feeling dizzy etc. 
So far so good, I didn't have any sort of side effects. 
How can I be sure that the pill I took worked???