Is Microgynon Pill Reliable To Prevent Pregnancy?

ok so i am 23 year old female who is on mycrogynon pill i already have a 6 year old daughter well at the moment i am getting pregnancy like symptoms although i have been bleeding! i get really bloated after eating and am tired all the time but do not have tender breasts. i missed 3 pills from my last pack what are the chances i am pregnant_