I NEED help! name brand to generic

I have been taking minastrin fe 24 for 6 months and I noticed I could get birth control for free and went and picked it up but this one is called microgestin and I was just wondering what is the difference and why is there 7 brown pills instead of 4? Does that mean I'll have my period for 7 days?! I really need this question answered so I can see if I want to go back to name brand.