Will i be covered?

I have recently have a stomach upset which occured about 2 hours ago, i took my marvelon pill at quarter past 7 as i do everyday. I know that stomach upsets(sickness/diarheoa) can stop the pill from working, but i read the leaflet and it said to just take another one within 12 hours if you're better-which i am. do you think this still means i'm covered. I would've thought the illness would need to be much longer for it to have an effect, but just needed some help..?