period on the pill

I've been on the pill since the end of August and I thought it was supposed to help with cramps and lighten your period and eventually make it go away. But me period hasn't changed at all since I've been on the pill, it's the same as it was before I was on it. It doesn't shorten my period either it still lasts like a week. Is it always going to be like this? Or will it eventually stop?