Could you tell me what happens if you don't bleed during the 7 day break on the birth control pill?

Depends: Some pills cause more suppression of the lining of the uterus, so that there isn't much lining to accumulate and bleed during the 7day pill-free interval; so that is not 'bad'or dangerous, but you would need sono/labs to make sure nothing else is preventing menstruation (like pregnancy...) . If labs/sono are normal then it is fine/safe to not have a period. If you want a period, may need to change.