I know that the pill less effective the less regularly you take it. If there's any chance that you might not have been covered then taking a test might be a good idea to put your mind at rest. That's what I'll be doing if my period is off when I finish this pack. Tbh, if you worry about it, it'll mess your body up and throw things off- although I'm not sure how much when you're on the pill. I know that when I had a 'scare' a couple of years ago seeing a negative test result brought on my period as I stopped worrying. I wasn't on the pill then though! Basically, if you think there's a chance you could be pregnant, however slim, then there's no harm in taking a test to put your mind at rest. And yes it is possible to fall pregnant whilst on the pill.
Hope that helps!!
Beca :wave: