Should i worry if my period flow has become heavier and started 5 days after finishing my last period even if taking the pill?

Abnormal bleeding: Abnormal bleeding can have many causes. If you aren't pregnant, start keeping a calendar of your periods, and if they continue to be abnormal then take this to a gynecologist.

Can happen not norma: Yes, not normal, may be break through bleeding on the pill, or something inside your uterus like a polyp or fibroid, or endometriosis, and must make sure u are not preg, so u need to see yoru gyn for an exam, blood work and an ultrasound.