Normally it's fine to take two packs of pills without a break, but I don't know about 3 - it's worth checking with your doctor.
And yes, 'periods' that you have on the pill are 'false' - the pill works in different ways - it stops eggs being released, makes your uterus less receptive to fertilised eggs (for those that get through) and thins the mucus that plugs your cervix. So, in answer to your question, you could still have a period if pregnant, although the chances you're pregnant (if taking the pill correctly, i.e. no upset stomachs etc) are low. Best do a test if not sure.