Break through bleeding is bleeding that happens when the pill isn't working well enough with your body to trick it into thinking it's "pregnant", preventing you from ovulating and preventing you from menstruating. If the hormones aren't strong enough, you'll start to bleed/menstruate, which means that type of birth control pill isn't working for you.
It could be break through bleeding or it could be something else, which is why I would suggest you see your doctor.
I don't think they are sugar pills. What is break through bleeding?
I'm a little confused on what you're saying? Are you skipping all of the non-active pills("sugar pills" with no hormones)?
It'd be a good idea to make a doctor's appointment with your gyno to see what is going on. It could be break through bleeding or another complication, but your doctor will have to tell you what is going on.