Why do i have really bad oily skin?

Okk so my face has basically always been normal. Not too greasy, or not too dry. It was never a problem.. up until recently. I'd have to say like about four months ago my face started breaking out really bad like on the sides of my face. They aren't nasty puss filled pimples or anything but they're those ones that look hard and when you try and squeeze them the inside of them is hard also. I have a few pimples that hurt but i don't mess with those. Anyway my face has become super oily. With makeup or without makeup. i hate it so bad! Within six hours of already having my makeup on, my face looks like i rubbed er all over it. =/ Why? I was using MAC for the longest. Not the liquid foundation just the studio fix powder. And i'd use covergirl foundation underneath that. And i thought maybe it had something to do with that, so i switched to Neutrogena powder and stopped using foundation, but it's no use. My face is still greasy/oily. And these breakouts are driving me insane. As soon as some start going away more pop out! UGH please help!! This is ruining my self-esteem.