I've Noticed, Recently, That When I Have Too Much To

I've noticed, recently, that when I have too much to drink one night, the following morning I have some vaginal spotting. When I'm a week away from starting my period and I drink too much, I have dark brown vaginal discharge the next morning. This only just recently starting happening to me in the last month and I have an appointment to see my doctor in a few weeks but I was curious as to whether or not you could give me some insight on what is wrong with me?