if this is your first time on any kind of birth control then I think it is normal to skip the first period, maybe even the second... I've never heard of a 28-day pack without placebos, though, so I don't know if that's affecting it - if I were you, I would call the pharmacist and ask them (when it comes to meds, they really know their stuff like side effects)...
hope this helps you out, even if it's just a little :)